Just FYI, Epcot hasn't had a capacity closing in a very long time, I think you have to go back to 2000.   So it's basically not a risk at Epcot.   Now granted, it's plenty crowded and a normally simple task of just getting around can be harder especially as the evening rolls on, but Epcot can really absorb people and people/crowd management is actually something Disney does shockingly well that day, generally speaking.  
To me, in some ways finding something to do to pass the time - eg, a longer sit down dinner somewhere - is important.  I wouldn't hesitate to book a dinner at an Epcot resort if there's a spot that appeals to your group. 
Have fun!