For character modelling and world objects, you'll have to get into a modelling program. You're probably not going to find many perfect free models, so you'll probably have to make your own.
Also, really specific things like certain character movements like you mentioned will have to be done in a modelling/animating program.
Of course, I always recommend Blender because it does everything you could want it to, and it's completely free. Some people complain that it's hard to learn how to use, but it's all about the time and effort you're willing to put forth. It's gonna take you a while to get good at modelling if that's what you need to do.