I know you can't trade Own Tempo Rockruff to SM, but can you trade it to another USUM game?
Yes. I have done this personally. I missed the event, so my friend bred me one to do a walkthrough with.
I don't know if you can do it with the originally distributed individual, but it would probably make the most sense to allow it if it's breedable. So I'm going to say yes to that too, but I can't confirm just yet.