Do you know that you can use the student version of all kind of autodesk products (max, maya, motion builder, mudbox…etc) for free. And functionally there is no difference between the student and commercial version. The only restriction is you can not use it commercially. As all your game assets will be imported to the game engine, you do not even have to think about it.
I do not know about the rigging system of unreal, but the rigging systems in max or maya are great. And if you use 3ds max’s CAT system, it will make things more easy. And retergeting in motion builder is a matter of few clicks. So, you can try this products and make your work easy.