Well, it turns out that I'm not such a shortsighted designer as I thought! =) Composing animations *seems* to work just fine, which is good, and actually the models are starting to look somewhat close to what I want.
Of course, the job now is to make one work product for each component type, which will allow exactly one animal model. So far, I have rump, waist, torso, body layout, leg, leg layout. Still quite a few to go, but, it's looking at least semi-natural =) and maybe by the time it's finished it will be acceptable. It will be accepted even if it's not acceptable.
I did make one mistake, and that is I should have implemented fliers before crawlers because most actual enemies are going to be fliers. I think crawlers will be more or less defenceless, maybe they will launch flames or spikes at you from the ground though, I don't know.