1. Yes, Morrowind will overwrite the previous game. Then on your account it will unlock the content. Your account adds content...you don’t lose it, so it’s not like upgrading to a new disc like morrowin will erase access to some previously unlocked area.

2. The game is getting older...but the populations are good. The chapters that are released in June being in tons of new players. It’s not as crowded as it once was, but you should be able to complete whatever you want to.

3. All of the classes are pretty good. For leveling...it really just depends on what you like playing. I like my mag Templar, stam sorc, stam warden and stamblade.

Something new since you played is the champion point system. CPs are earned by vet characters and are added to your account. All characters, vet or not, may use the total number of CPs you’ve earned. The reason I mention this is that CPs act like miniature attribute points, slowly fine tuning characters. This has served to bring all of the classes closer together because the CPs help a character of any class overcome their weaknesses. Nightblade gets far tankier with CPs, and dragon knights can increase their dps. When you last played the classes has massive benefits and drawbacks...the game doesn’t quite play like that now, all of the classes can be fun.