Hi ,
I am the primary blender user for our team but, unfortunately I don’t have much experience with animation. Would you mind sending me a sample blender file that is exhibiting the problems you are describing along with what steps you are taking when importing the model to the engine? I would be more than happy to test it on my end and see what may be occurring. Note: If this doesn’t require animation and just a skeletal mesh please let me know, I have several laying around I can try importing.