I think Mudkip. Or Pochama. Swampert with an Ice Beam will cover its weakness and... yeah. Though, having to split between Att. and Sp. Att is annoying. Endevour is sometimes a lifesaver.
Truthfully, I think they're all cute, but I have to go with Pochama. Pochama is the cutest thing and it's so small! I wish I could go and hug him like the world will end in 4 seconds!