Train Types - ICE & EC

See train fleet information of Deutsche Bahn.
ECs are in most cases operated by railroad providers from other countries, e. g. ÖBB or SNCB.

the three fastest types of train in Germany are ICE, EC, IC

The fastest are ICE - Inter City Express. Sleek, usually white, aerodynamic, travel at up to 300 kph (186 mph), fewest stops, most comfortable (to me)

IC - Inter City - somewhat slower than ICE, usually run on conventional tracks, connect cities within Germany, usually somewhat older but good train stock

EC - Euro City - the same as IC, but international. Run on much longer routes, often through multiple countries with the same train number, and sometimes name. Usually the train stock travels through but the train crews change near the borders. Depending on who is providing the train stock it may be a little older or newer, with different configurations of seating. When you look up in Germany and see a Swiss or Belgian or Dutch or French or Czech or Austrian passenger train it likely has a EC number.

I imagine the advice to stay on ICE trains is due to fewer stops and faster service, not so much comfort and other factors. If you are already thinking another route will be easier on you, albeit longer time, then go with it.

I do the same, look at times and changes, as well as departure or arrival time, then pick the one that makes sense, rarely concerned with train type.

I suggested using the EC train on your previous post. You were concerned about making connections and one way to alleviate that is choose a route that makes fewer connections. The EC train leaves about 30 minutes later than the ICE train, and it makes more stops than the ICE train, but eliminates the need to change trains in Munich. The EC train starts in Frankfurt, so there is a good chance it will depart on time. The ICE train starts in Essen, stopping at various points, like Duisburg, Duesseldorf, and Cologne, which are all opportunities to run into delays. As far as train comfort, I would not be too concerned. Both trains have restaurant/snack cars if you want something.

There is a difference, but not a big one. After high speed trains, EC is the highest category of trains. And if an EC train takes me to my destination, I would not hesitate to book it. I guess you're looking at the Frankfurt-Graz EC train, which is an Austrian train and no reason to complain about the comfort in that train. There is an ICE a few hours later but there is no time advantage to the ICE.

Thank you all for the train advice. I appreciate all the input. We ended up booking the itinerary with a combo of ICE and EC trains, primarily due to the least amount of transfers. Oddly enough, we were not able to reserve the Bruges to Brussels leg; it appears we can reserve that leg only starting on March 24, something about 30 days....? So, my calendar is marked.

Of more pressing concern, when I was completing the booking, I didn't see any prompts to put the other passenger names in. So, my Online Ticket says 4 passengers, and I paid for 4 passengers, but it has just my name on the ticket. I've tried to send an email to DB but it failed to send. Will my ticket allow all of us to travel? Further advice/clarification about this concern is very welcomed. Many thanks.

No DB does not care about your traveling companions, only that you paid for them and they are with you. So when the conductor comes by to check tickets, just identify yourself as the lead traveler, show the ticket and indicate "These 3 people are with me."

I doubt you will need a reservation for the Bruges-Brussels train. it is virtually a commuter train with one 4 times every hour direct to Brussels. Bruges is just the second stop on the way so there should be plenty of seats and you can get your pick. It will get busy as it closer to Brussels, but you will already have your places. It is only in midi station for 3 minutes, so have your luggage gathered and be standing in the vestibule when it pulls into the station so you can hop off right away.

Oddly enough, we were not able to reserve the Bruges to Brussels leg; it appears we can reserve that leg only starting on March 24, something about 30 days....?

No need to reserve, nor probably able to reserve, this is essentially a regional train. If the price of that portion was included in your ticket, then you're set. Just get on and go. I do not believe you are even restricted to a certain train, if you get to the station early, and a train is headed to Ghent or Brussels, hop on.

"ECs are in most cases operated by railroad providers from other countries, e. g. ÖBB or SNCB."

That is incorrect. These trains are operated by DB when in Germany. International trains to/from Germany are still operated the way international trains everywhere in Europe used to be operated. So an EC train from somewhere in Germany to somewhere in Austria will be DB operated till the Austrian border, and OBB operated from there on. You will see that the crews change at the border. An Austrian driver takes over, and Austrian conductors board.
It is the same with the ICEs between Germany in Austria: for the Austrian part of their trip it is the Austrian railways that are the operator. You can see that on www.bahn.de if you want.

So the logo on the train, and its colour scheme do not determine who operates it.

Back to the OP: I would just booked the fastest connection. Changing trains is trivial, and does break up the trip a bit. It is long enough as it is already.

Regarding reservations for Bruges - Brussels: You cannot reserve seats on Belgian domestic trains. The Belgian train network is basically a commuter train network centred on Brussels. Think Metra or Septa. That also means that by all means take an earlier train to Brussels if the efficient connection makes you uncomfortable. Trains run several times per hour.