Given that the other offers say "includes 50 USD resort credit per night", I'd bet the $25 credit on this offer is once per stay. However, the text is a bit unclear.

The suggestion of booking four separate single nights is a waste of time. The hotel will still view it as one stay, regardless of how many reservations are used. (Actually, it appears that the FL resident rate is not available for 1-night stays over Thanksgiving. So, that strategy isn't even possible.)