re: Last minute trip to gulf coast and can't decide where

Look at Destin West Resort in Ft Walton

Seems like it might work for you if it's still the same set up as last time we were there several years ago. The property has a beach side and a bay side with a walk over bridge connecting the two.
The bay side has a nice pool with a lazy river. On the beach side, there is a hotel next door. They used to let you have access to use their property and there was a small kids splash park and a very nice pool with a waterfall over a swim up bar. The hotel had kids activities as well.

The beach was not very crowded and overall it was nice being away from the crowds of Destin.