Hi!
I started out playing BG now with my sister in a multiplayer game. We can't make up our mind if we want to have our own characters or pick up the NSC people. As I read through the forums I understand that depending on which people you have in the group you get different quests. So can I play them all? Picking up and later kicking out people? Since we had so much fun making our characters we don't want to kick them out...

I think it's possible to do all NPC-related quests but there are also quests that depend on which class your PC is.
But I think you shouldn't do them all in 1 game.
It's much cooler to start a new game and do quests you never did in the first game.
Your characters will also reach higher levels than when you take a NPC, do their quest and kick them out of your party (xp = divided evenly over your party so you throw xp away when you kick someone out)

yeah he is right dont try doin all the quests in one game try differnet quests and charaters in different games it makes it moer fun.