Well, I've tried a bunch of times now and I can't get this process to work for me.

 

If I unify texture co-ordinates, it resets any editing I did to the UVs in Marv.  (Moving, Scaling, rotating, etc.)

That aside, when I transfer attributes in Maya, the flattened quad does take the shape but the UVs seem to go away with no way or option to save them.

 

In Max, the quads are mixed with tris still, and the quads are vomited out into crazy configurations that don't really satisfy.

 

I'll keep trying, but I must be doing something wrong at some point or another.