4 country pass or global- new travelers, no precise plans...

I would buy a pass for Switzerland and not a Eurail one. Either the Swiss Travel Pass or Half Fare Card.

However look at buying individual country passes and not Eurail.

You may be looking for spontaneity of train travel but you have to read thoroughly everything to see how it works in your travel plan before you buy a pass.

There is no cut and dry hop on show pass hop off and so on. It seems a lot of people go into Eurail pass thinking that way,

You might for each country or area (e.g. Benelux, Swiss, Italy and France) you plan to travel to post a separate question asking:

"I am going from this country to this one where I am planning to stay x amount of days. What kind of rail pass do you recommend I buy?"

Call me a pass hater, but they just have too many strings attached, and as you have pointed out, represent a massive outlay of money before the trip has even begun. But then I have everything pretty well planned out before hand, so can buy nonrefundable discount tickets.

I assume you are aware of the caveats.
1. Very high reservations fees to ride the Thalys train. Stick to IC trains.
2. Reservations fees of about 10 EUR pp for Freccia trains in Italy. Less for iC and EC trains.
3. Reservation fees for French TGV trains.

What day trip do you have in mind to add Germany to the pass?

I generally make my own custom spreadsheets. And the information for in-put is more important. "Garbage-in, garbage-out" as the computer programmers used to say.

There is a calculation program by Rail Europe.
https://www.raileurope.com/train-tickets/train-tickets/

Before committing yourself to a rail pass, read carefully the advice of the European rail expert Man in Seat 61: railpass-or-point-to-point-tickets. When doing the arithmetics you should compare advance-bought tickets with the price of a pass, including the reservation fees. The high-speed train from Rome to Turin (Torino), for example, costs you EUR 98 when bought a few days before departure, but only EUR 49 when bought one or two months in advance.
And rethink your plan to go 1st class. Again the Man in Seat 61 gives the answer: First or second class? No European travels 1st class, unless the boss pays for it.

The pass will not save you any money in France where the reservation fee for the TGV in first class with a rail pass is comparable to simply buying the ticket/reservation separately. The big plus to a rail pass is flexibility. However, you seem to have a pretty set itinerary. Do you need that level of flexibility or could you simply do advance purchase point to point for tickets outside of Switzerland?

Thanks everyone so far for your help!
I had read the article about first class and i definitely think second class is really more our style, but I'm confused because I've read 2x now in other articles (one here: https://www.nomadicmatt.com/travel-blogs/eurail-passes-breakdown/) that if you are over 28 you have to buy first class. Is that incorrect?
I guess I'll play with RS's rail maps and the RAIL EUROPE site for a bit and see how costs add up.
I think part of my problem now is that I am imagining going all over the place in a "eyes to big or my stomach" sort of way.

I've read 2x now in other articles . . . . that if you are over 28 you have to buy first class. Is that incorrect?

That is only for Eurail passes. Us locals just buy tickets, in advance if possible to get the best fares (unless it is for work at short notice) and travel 2nd class (unless the company is paying or there is a really good deal).

I guess I'll play with RS's rail maps and the RAIL EUROPE site for a bit and see how costs add up.

Don't. The RS maps are "pay on the day" prices. In many cases you can get big discounts (50% or more) for buying weeks or months in advance, direct from the company running the trains.
RAIL EUROPE only sells some tickets and doesn't cover all routes. It only sells the more expensive tickets it can make a profit on.
There are many local offers sold direct by the railway companies, for example the one-day-passes covering German states (Länder tickets), which are very good value.
Read this webpage about how to buy tickets: https://www.seat61.com/Europe-train-tickets.htm

I think part of my problem now is that I am imagining going all over the place in a "eyes to big or my stomach" sort of way.

A common problem.

"...no precise plans... I think part of my problem now is that I am imagining going all over the place"

So it's Aug 17 - Sept. 5, correct? I count 19 days. It depends how often you change towns, but I believe a 15-day pass might be overkill since that would mean train trips nearly every day. Perhaps a 10-day pass would be more in order if you are planning to stay an average of 2 nights in each place (which is still pretty fast.)

I would normally suggest that you get your destination priorities in order prior prior to worrying about which pass to buy.

In your case, there is one pass that you should think about as you plan... This pass is valid for train travel in all of Germany, and to certain locations in several countries, including the Benelux countries (From or to Brussels and Liege by ICE train; Amsterdam, Maastricht, Gent, Antwerp using the German Railways IC Bus - some restrictions, see details) as well as train travel to the French and Swiss borders. A twin-pass in 2nd class, flexi-version, costs €267 each for 10 days, €208 per adult for 7 days. See links below for the German Rail pass:

https://www.bahn.com/en/view/mdb/bahnintern/international/redaktion_bahn.com/pdf-datein/pdf_2018/mdb_268059_german_rail_pass_2018.pdf

https://www.bahn.com/en/view/offers/passes/german-rail-pass.shtml

Except for the buses, no reservations are required for using the German Rail Pass. Just hop on.

Perhaps you would want a Swiss Rail pass for a few days on top of the GRP.

Transport from Germany into France at the end of your trip can most easily be accomplished with a pre-purchased saver fare tickets - check the DB website.

It is less hectic and stressful if you book stays of 3+ nights in each destination. So I'd suggest 6 different base towns as a maximum number. My guess is that you will actually see and enjoy more if you attempt fewer countries and overnight stops. That means a 7- day pass would cover most of your trip (or perhaps all of your trip if you left out France and Switzerland, which is more expensive than you can imagine.)

Of course, it would be perfectly possible to have a very nice 19-day trip that is built around only the GRP, which includes travel to Prague, to Salzburg Austria, to Venice and Verona and the Italian Alps, and to Copenhagen as well.

Second-class versions of Eurail Global and Select Passes are now offered to travelers of all ages, as of this spring. A 10-day flexi saver pass in 2nd class currently costs $587 per adult on the Global pass or $518 for a Select pass in those 4 areas. The 15-day flexi saver Global pass is $768 per adult.

It's hard to compare costs without a fixed itinerary but I think our ticket-cost maps are indeed a good place for you to start. Yes, they are full fares for the faster trains. Advance-purchase ticket discounts are also available, but they'll lock you into particular travel dates and times, which you don't sound ready to do. The best advance discounts are also already sold out, though lesser discounts remain on most routes. Any of the discounts is offered on a limited number of seats, so I would only spend time looking them up if you're pretty close to being ready to reserve.

Most trains in Benelux, Germany, and Switzerland don't require seat reservations with a rail pass, but as already mentioned, Thalys in Benelux or pretty much any long-distance train to/from/within France does require them. Reservation fees for those are higher in 1st class, so that's another reason that I'd be looking at the 2nd-class pass. Fees will not cost the same amount as a train ticket because (again) the cheapest tickets will already be sold out for your travel period.

I don't know what route you're considering between Italy and France, but here's an example for the direct trains from Milan to Paris on Sept. 1 (per person but based on 2 people traveling): 6:00 a.m. currently available from €69, 8:45 from €79, and 14:40 from €74. Ticket prices will rise as the trains fill up. Passholder seat reservations cost $41 per person in 2nd class and could also sell out, but not right away - they're still available for this Saturday, July 7, for instance, or other ticket prices on that date are from €104 at 8:45 and from €79 at 14:40.

Probably an even better option would be to fly between Italy and Paris; see www.skyscanner.com. Ticket prices between $50 and $120 are common from any main city in Italy and that flight could trim down the number of days and countries that you'd consider on a rail pass.

I do not recommend re-posting this question in multiple country pages. It's the whole plan that actually counts.

Around the Berner Oberland area (up valley from Interlaken), Eurail-brand passes only give you 25% ticket discounts, but those discounts don't require using a counted rail pass travel day. The Swiss Travel Pass or Half-Fare Card give more coverage but follow different rules about using a pass day. See https://www.ricksteves.com/travel-tips/transportation/trains/switzerland-rail-passes.

Thanks so much for everyones help- you are all so incredible to give time to share your expertise and experience. :)
We purchased a flight from between Venice and Paris (No offense, but we are not big city people and we wouldn't even go to Paris except we have to get back to USA and thought why not Paris too (cheapest flight home we found along our route). We will be riding with family between Hasselt (Belgium) and Kandersteg (Switzerland), so no cost there ( and potentially limited cost while in Switzerland due to having a car on hand but we all want to enjoy the trains so not sure if we will rely on much car while in Switzerland). We are trying to swing it with perspective of train travel mostly so we don't burden family with car travel (trains are fun for everyone!). We do however need a train to Venice from Kandersteg (90-145$ each per Rome to Rio)...
Im getting closer and closer to just purchasing tickets there one by one... if discount tickets are mostly sold out- then cest' la vie. I tried to keep track of this early enough to be smart about it but maybe we just have to wing it and learn a lesson.
So- Italy Switzerland pass is currently $269 per person, discounted assuming we travel together. THAT might help us- as it will cover Kandersteg to Venice and some more (as long as our other travel costs add up to $169 or so (taking into consideration that it only gives partial discount on many trains....).
What i see ultimately- is it's a gamble unless you are train route expert / hacker! I think the time it would take to tally every route (with potentially inaccurate $) might "cost" me more than actually buying the tickets in the grand scheme of things.

We can't wait to figure it out! LOL... We'll get there one way or another and it will be beautiful :)