8 days Paris & Como

8 days is not a long time. You are right to limit it to 2 places.
Lake Como is a lake, you are actually going to the town of Tremezzo, that makes a big difference
1) If you are going from Paris to Tremezzo, the Bernina Express does not make much sense. Neither does picking up a car in Zürich, as you would then have to return it to somewhere in Switzerland, and you want to fly out of Milan.
Tremezzo does not have a railway station, the nearest ones are Lugano or Como (the town).
2) If you want to spend time in Florence, that would be instead of Lake Como, you do not have time for both.

I would recommend the train from Paris to Como (the town). Pick up a car there and drive to Tremezzo. Flying would not be much faster, the end-to-end journey time would be about the same, and by train you get to see the Alps. Go to www.sbb.ch enter Paris to Como S. Giovanni, and a date and time.
That gives you plenty of places to explore around Lake Como, no trouble filling 4 days. Lugano is a good place to spend one day.
You can then drop off the car at Milan airport, and fly home from there.

Well, since you say any thoughts are appreciated AND this is your first trip to Europe and you won't be back for a long time, I would suggest you get the most bang for your buck that you can. Paris is a fantastic choice. And since you're set to fly from Milan, I would add Venice as my second city. The Lake Como area looks beautiful...I've never been there...but if this may well be your only trip to Europe for another decade, go to Venice.

I'd also suggest limiting your 8 day trip to 2 locations.

Whether you choose to take a train from Paris to the town of Como, or fly from Paris to Milan, you will basically use up a whole day
traveling from point A to point B.

Having said this, that only leaves you with 3 days to enjoy Tremezzo on Lake Como.

You also need to consider that you will need to get to Malpensa Airport at least 2-3 hours before your flight, so will you be spending the night before your flight in Milan?

If so, then you will only have 2 days to explore Tremezzo.

Tremezzo is a town on Lake Como & you can reach it via bus from the town of Como or via ferry.
Once you reach Tremezzo, you can easily visit the other mid-lake towns/villages, such as Varenna, Bellagio & Menaggio.

Another option is to travel to Stresa on Lake Maggiore.

Lake Maggiore is closer to the Malpensa Airport than Lake Como.

I presume you've already booked your flights. If not, I'd say stay in Paris & travel nearby for the 8 days.

If you've already booked your flights, you may also consider traveling to Venice or Florence.

Enjoy your trip!

With only 9 nights, I would try to cut out travel time and concentrate on one country.

If you have your heart set on an Italian experience during part of those 9 nights, okay. There are other options (see below).

You didn't say why you chose Lake Como (proximity to Malpensa?). Or was it because it would be idyllic and a change of pace from the big city (Paris)?

If that was the case, I would suggest after Paris to travel south to the French Riviera. Take the TGV (it's an impressive feat of engineering that Americans have not mastered).

Nice is a small city that is on the Mediterranean. It's one of my favorite places. Being by the sea is just magical.
What's also great about it is that it's on a train line so you can daytrip to many little towns (Cannes, St-Tropez, Antibes, etc) or Monaco along the Riviera whenever you want. The time of year you're going is perfect for visiting Paris and the Riviera.
I was there in 2014.

Or you can stay on the Italian Riviera just east of Monaco. In any case, there is a train line that runs from Nice to Genoa and then Milan (if you must depart from Europe from this location).

Gotta say, if you really want a vacation that is relaxing (less driving) with beautiful scenery; very different from the USA; has great food, a Mediterranean portion for your trip would be perfect.

P.S. Lake Como, as a region, is pretty but very "calm". When I visit there (I stayed in Bellagio and ferried over to the towns of Menaggio & Varenna), I thought it has more of an atmosphere for honeymoons, retirees and laid-back families. There are nice hiking paths along the lake and the towns are quaint. You can also visit some stunning lake-side Italian estates with beautiful gardens and views. If this is your thing, definitely go with Como. There are periodic trains (I believe) from Como to Milan.

P.P.S. fyi, there is an overnight train from Paris to Milan. Saves time.

Bon Voyage!

Another vote for Stresa on Lake Maggiore. Ferry to the most marvelous islands to visit for a day trip, and a very short hop to Malpensa.

I agree with my fellow posters that you should try to have only Paris and one other destination. As much as I love Lake Como, since you won't be back for a while, I would take the two hour flight to either Venice or Florence and stay in one of those. You won't waste a day traveling compared to taking the train. Venice is a unique city because of its canals. Florence of course has some of the most magnificent art in the world and only a one hour train ride to visit Pisa for a day trip. Research both and see what they have that would pique your interests.

After many European trips, with the dollars invested in airfare and lodging, I'm a believer in minimizing time spent traveling point to point. As a Rick Steves' tour guide once said "Lets not waste precious time."