I originally had a much bigger list, but these four embody just about everything that I want in the art.
Rayquaza PTank, Kangaskhan STank: I think that CAP 1 should have a sort of "armoured" feel to reflect the bulk that it has (Rayquaza/Kangaskhan level).
Omastar offenses, 85 base Speed: This reinforces the "armoured" feel "requirement" that I have, suggesting that CAP 1 shouldn't be all that large and not give much of an indication of high or low Speed.
Abilities: I really, really like how all four of these incorporate both Prankster and Intimidate (intentionally or not) into the concepts without merely using facial expressions to do so. I can really see all of these giving an intimidating feel and yet also having a playful side.
The order was very, very hard, and I wish that I could rank them equally. Doug's is last only because I couldn't see it using the mandatory Fighting-type moves Rock Smash and Strength; I had to resort to that criterion to decide... I'm really, really glad that Cartoons!'s design went through as well. I may have ranked them in a certain way, but my very thin preferences are definitely subject to change.
EDIT: I now have a fourth criterion in which I want a pure Flying-type pre-evolution to justify the primary typing a bit more. I have rearranged my vote accordingly.
Cartoons! because it is my favorite. Mektar because it makes me lol... 'nough said Energy Storm because it looks spiritual (is that a word and did I use it right?) Wyverii because... Honestly I don't know why, but I like it