umm i got wrong the attacks, was pretty sure that they mentioned chillarmy learning helping hand..... o well.. anyway..Chillarmy has Sweep Slap, not Double Slap. I also don't see a tail so I doubt it. Have we seen Chillarmy use Helping Hand?
Even ignoring the color thing, it'd be weird for it to lose its tail...and well everything that made it identifiable.
Tabunne is perfectly upright, has no tail, completely different ears, markings, disposition.
Level 10 would be a pretty early time for a non-bug to evolve, too. Why not just show Chillarmy, you know?
tabunne seem to have a tail that can be see under his left arm.. or what i think is part of a tail,
esnubbul to granbull lost/change almost all the things that were remarkable (dots, ears, hands, dress like body, color) but the face is quite similar especially the eyes .. and for what I remember eyes are quite charasteristic of each poke, at least in Ken Sugimori art.
and about the level.. well we have meet underleveled evolved pokes before.. and this is a demo
the rest is like you say.. ^_^.. obviously I could, and almost certanly, be wrong XD but is an interesant proposition.. tabunne could be based in a giant gerbo-like animal (against my theory ... it looks more like a standing dog)