Colossal Titan threw it back too hard and now he's stuck

I just about managed to get this Colossal Titan avatar working, but I ran into a problem. He’s all hunched over and his butt’s sticking out. Is there anything I can do to get him to stand up straight?

Here’s an Imgur album of what’s going on.

The preview works just fine, even if his shoulders are up a bit and his jaw’s hanging open.

Update: So I think I gained some info. When I set Standing Locomotion to idle3, he stands up straight, but only when moving, so his legs don’t move. I had to change it back so his legs would move when he moves, but I think the answer is that I gotta put idle3 in the right spot.

Update 2: Alright, so changing the idle animation didn’t fix the problem. Ugh… He looks just fine in the Unity animation preview.