Say your doing a team of 4 shamans

I already have 4 accounts, mind you not active. Now I really do not care about the Zhevra mounts and how many whoever gets, my main question is this.

Say I Create a new account with RAF, are there any leveling retrictions or only 10 days? Or like is it level 20 until they upgrade?

Do all characters in the group get the experience or just the two accounts that are linked?