OK, got it worked out and I will be fine, considering I was kind of scrambling.
First off, United just let me cancel my ticket w/o a change fee. It's travel funds, but I'm sure I'll use them no problem.
Taking a redeye from SFO to IAD and then IAD to CUN on United for 17.5k (economy saver) each, get into CUN at 9am. Had to use a few Sapphire points but well worth it IMO.
On the return, had two main options:
12.5k AA points/ticket (which I had), leave at 1:00pm, get to SFO at 10pm
13.5k SW points/ticket (which required 22k Sapphire points) but leave CUN at 4:15pm and fly into Oakland at 11:30 instead.
I went w/ good ole southwest.
One question though - United hit me w/ a $50/ticket booking fee for award travel w/in 21 days. Because of the circumstances (weather) any chance I could get them to wave it? It's a separate reservation so I doubt it.