I'd say that the strongest allrounder is still Bigfoot, as he has better stats than the unique Characters.
Werewolf is focused on fast attack patterns with less power and no tanking
Bigfoot is pretty much avarage in all stats which makes him usefull
Balaphant is focused on tanking, his roll attack is useful dureing the starting phase of a raid, less when they start to surround him
I haven't checked the white tiger yet, but it would stand to reason to assume he is focused on damage I gues.
The goat seems to have more combi attacks that can deal avarage damage in fast succession, but overall hardly any tanking and rechargeing those Combos take time