The FHR welcome paper they give you at check-in says "breakfast", but they simply credit it when you charge to the room. I would guess it would work just fine.
Simple DP, I didn't get offered any upgrade (which seems standard for this property, it was very busy...), but I did manage to get Marriott points + elite nights for the room charge + spa charge. I had to add my Marriott number at checkin, but after that still had to submit a missing points request via Marriott online form. They processed it very quickly (~48hr), though that was before the system merge...
I signed up for the Identity membership after checkin (hotel-specific rewards program), and they give you a card to present if you gamble/shop/eat at the hotel. I used it for some of the nice restaurants and got a reasonable sum of points, though since I had my Marriott number attached to the room, only the F&B room charges went to Identity (per program terms)