luv2vacay

Pardon the stupid questions, but I'm not terribly familiar with UA in this regard (or any of the other airlines, for that matter, LOL)

Flight was booked (not by me) by partner.
8/30/19 ALB to DEN via ORD (UA 2133 and then UA 501)
return
9/1/19 DEN to ALB via ORD (UA 830 and then UA 785)

In coach/economy (not basic economy)

On the UA 501, he picked "bad" seats, so I'm paying to upgrade/switch to econ plus (First is all sold out)
It'll be like $235 or thereabouts (ouch), but better than a limited recline seat, IMO.

Anyhoo:
I can Upgrade with miles, on the outbound (ALB to DEN) for 17.5k miles plus $75 each and waitlist the ORD to DEN (highly doubt it'd happen as everything indicates these are really all sold out as it's the nice seating, LOL).

On the return, if I upgrade with miles, it's 20k miles plus $75 each and waitlisted on all flight segments.

The two questions I have are:

1) If I pay for the econ plus, and later get the waitlisted upgrade with miles, what happens to the paid econ fare? I'm assuming it's gone/not refunded?

2) If I pay for an upgrade to First on say, the ALB to ORD (I wanna say $141 each), and then upgrade with miles and it all comes through, what happens to the $141 each upgrade? (Refunded, just chalk it up to oh well, etc.?)

Of course, this assumes any of this is "wise" to upgrade with miles, I have to figure out if it's per segment or the entire way (17.5 each on the outbound, not per segment) and then figure out the cost/mile. Obviously upgrades are subjective in some terms. So far, not looking like a very good redemption, unless it's 17.5k for the entire way *and* both segments were to clear. At least if I'm doing my math correctly (something like $0.008/point for the one segment).

Thanks in advance and sorry for the dumb questions.