if by special attack you mean like for flame thrower and things like that, you should keep him on all 4s. really i'd say keep him on all 4s for all the poses. unless you want to randomly have is idle pose on 2 but besides that, or maybe even have his physical attacks on 2 like for areal ace and brick break. (and yes i know that your poses are for general physical attacks and special attacks.) i'm just letting you know that some of quilava's physical attacks are more used with his hands/front paws. the only exception that i can think of as of now would be flame wheel, which is pretty much a takle with fire around him. so people could use the walk poses for that. after looking at his move set really just about all of his physical moves, (with the exceptions of roll out, double edge, and flame wheel) quilava would more than likely use his front legs/hands. (also an exception would be double kick, and flare blitz,). in other words you should make quilava's physical attack do something with his front paws/hand/legs instead of like some kind of tackle, since the majority of his physical moves would use them. The other tackle like moves people could just use his running pose.
PS: i only say so much about him because quilava's one of my favorites.
PS: i only say so much about him because quilava's one of my favorites.