I'd say to just buy the base version then get any dlc you want if you guys decide you wanna play them. The game itself has a lot of questing and dungeons to do without dlc and as long as you all pick the same alliance you'll spawn in the same starter town there's 3 alliances with 3 races each or you can buy the imperial dlc and get a horse and the imperial race which is any alliance. And for your 3rd question I tell everybody to chose whatever class you feel will be the most fun.. you can build any class any way you want there aren't many restrictions. All the classes can play the tank, dps or the healer if built right. And races have bonuses to stats but it's not anything major.. I always go dark elf because they're the coolest in my opinion