Original poster did not indicate whether they were interested in PvE, PvP (battlegrounds or arena), etc..
Just that they were interested in boxing, and a few combinations.
They pretty much asked generic questions...



I ran 5x Ferals in battlegrounds, up until they removed powershifting - breaking roots and bersker - break/immune to fear.
On PTR at the moment, Dash and the 83 Roar both break root and make you immune for the duration; while not ideal (nothing but trinket against Fear), that's still 40 seconds (every 3 minutes) of AoE/Party/Raid root immunity plus the duration of Dash (Self).
I could see 4x Ferals, with a healer as being decent in arena; probably not a top team, but far from a bottom choice.


Four Shammies and four Warlocks are both fun teams.
I could see 4x Shamans as heroic/instance viable, if they had a tank or ran random dungeon finder.
Not sure if OP wanted to run PvE or PvP really.