imo maybe other ppl can manage it ez, but chosing a 2 mele dps is kinda difficult for me to manage, especially if one of them is a rogue where i belive some hits requires to be from behind, since am kinda slacker 1 mele dps is fine, others ranged dps and have the mele as a master, while others assist,if u gonna pick a healer it doesnt matter really coz u can treat healers as casters where u do not need to be in special position.
as for the second Question, am not really sure but i chosed 5 shamans because its ezier to manage and they look kewl , u can do as just fine with anything u chose as long as u can manage the other toons