Alright! I have done what I set out to do in the original post.
I didn't bother asking MS if they could reallocate for me as I knew what the "official" answer was and I didn't want to take any chances of losing my Aulani reservation.
It was my first time calling MS, so that was fun.
Here's what I did:
1) Found a 24 point reservation. For anyone who cares, it ended up being a 1BR Villa Resort View at Boardwalk on a weeknight in June.
2) Called MS. Requested to make that exact reservation, and to purchase BOGO OTU points to do it. For anyone who cares, the call lasted just 12 minutes. Paid my $240 and had the reservation in my dashboard right away. (And FAWC...my OTU were from VGC. Fancy! LOL.)
3) Hung up and cancelled the Boardwalk reservation, immediately freeing up the 24 points to be used within my 2025 UY for a 7mo or less reservation.
4) Went to modify my existing Aulani reservation. This is the part that drove my pulse up, but it was just a lot of clicking through without changing anything, until it showed me my contracts and points. I was able to choose the order in which to use them, so I labeled the two OTU contracts (one contract for the points I bought, one contract for the points I was "gifted" via MMB) as 1st and 2nd, and my actual contract as 3rd.
5) Ta-da! I now had 24 points remaining in my 2025 UY, and I banked them to 2026 because my goal with all of this was to make a 2026 UY reservation without borrowing from 2027.
Thanks for all the tips and backup. Hope this helps anyone who may find themselves with a similar desire and plan. I feel
DVC savvy.