Took a look, and yeah, wow. That took longer that I expected. To be honest, I’m still not 100% sure what the issue was, but I got it to import properly into engine. Can you access that location? I put a file up there that has the fix.
Things I did:
-deleted non-deformer history on meshes (didn’t work by itself)
-exported skin weights on meshes
-deleted all history on meshes
-froze transformations
-imported weights
After doing those things, it worked!