No matter what I do however, when I play the animation the hands (which are set in a default T-Pose position) show up like this in the animation. The pinky and the other fingers spread out awkwardly.
Fixed my problem, going to post the solution in case anyone else has the same issue in the future. I took the fbx into max and deleted the Index0 and Pinky0 bones then parented the pinky1 and thumb1 bones to the finger base and all is well
I had the same problem. I went to fix it in Max using the steps you describe, but when the FBX file opens in Max, the eyes, teeth etc are all out of place (and continue to be if I make the changes and export as a new FBX). Is there some setting I’m missing on the FBX import dialogue? Any help is very appreciated - I’m using Max 2012 x64