The tranny is already reassembled, and I doubt the shop would have been game for welding tranny internals. Modifying oem, heat tempering and whatnot.
I guess the other question is was the cir clip the chicken or the egg. Could bearing failure have led to the cir clip vibrating free which caused more destruction, or was it the cir clip coming free that caused everything.
In my searches for the whining issue I never came across the clip failure like yours, so hopefully its a fairly uncommon thing as I assume this is a pretty generic design across the Subaru range as most other things with Subaru.