I did Venoxis and Jeklik yesterday with the help from 3 friends.
Maybe not that useful information since 3 characters were played by live players. But hey, might count for something.

Boxed Characters:
4xWarrior (2 of them tank and the 2 dps were lvl 59)
Shaman Healer (lvl 59)

7 Mages
1 warlock
1 Priest Healer

Live played characters by friends:
Hunter
Warlock
Resto druid