OP here -- just some feedback on what actually happened. Accepted UFC buyup for both myself and wife while miles + copay u/g award was still pending, uncleared. After 4 weeks, neither miles nor copay were returned (no intervention on my part during that time.) Called MPSC, got very competent person who returned the miles instantly, and put in for the copays, which credited on my card a few days later.

My account log shows that UFC leg as flown in the "ZN" fare bucket (original class of service was L). One might guess that the UA software that decides whether or not an award u/g cleared might simply look at the class of service actually flown, and use that as a decision on whether to issue refunds automatically. Since in this case that basis put me in J, I guess I can see why no auto-refund occurred. I do recognize upthread that some people seem to have had a different experience in this circumstance, so my contribution here is simply to state that the award refund is not always automatic when the u/g was ultimately purchased a different way. The MPSC agent was a pleasure to deal with, so this was a very small hassle indeed.