1. you can have a total of 8 game accounts on one B.net account.
2. Not sure But I would go with Blood DK
3. Don't know
4. yes it is easy. I am currently boxing upto 11 teams with my 90 days RAF exp. so far 30 days are up tomorrow I have one team at 85, 70 45, 42, 40 40 and I have been going slow.
5. Don't know never boosted on ran teams of equal level.

BTW RAF is to 85 now too.