make sure he gets his RPU back as well (unless it was "spent" on a preceding segment...i'd still email a request for it anyways, worst they can say is no)

OP, i dont think that downline segments are prioritized differently when one segment clears. if you are not optimistic about clearing IAH-SFO, you can request a redeposit of your RPU - provided that your original coach fare class is available on the MSY-IAH flight.

i'm not sure how C/Y ratio is on the 787 but that is the number that matters, not the total number of C seats. if the flight has 100 C seats, but 1M Y seats, the upgrade chances still arent that great. extreme example but you see what i mean. this is why upgrades on A320 are tricky especially V2/V3. terrible F/Y ratio IMO.