Looks awesome MotorRoach. Obviously, this is still a work in progress, so you may have been planning it anyways, but I have one suggestion, which I think might add a bit more impact to the animation.
When Knuckles finishes his animation, the last few frames are quick and give him a bit of a bounce/powerful finish, arriving at the final pose with a strong impact. I think it would look good if Sonic and Tails had that same kind of bounce/strength at the end of their animation.
Aside from that, I have nothing else to add. The characters and their poses all look awesome.