When we stayed there in 2012 you could not charge food/drink to your room at Toppers by the Sea (the restaurant on the beach at the Flamingo, not to be confused with Toppers on Welfare Rd). The same goes for the pool bar which is run by Toppers also. We thought the food was OK but a bit over-priced as were the drinks. At that time there was a Tiki-type beach bar with a limited food menu a little way down the beach which we liked for lunch. I think it is operated by Simpson Bay Resort which is next door to the Flamingo.
As for the seaweed issue, it doesn't appear that it is as much of a problem in Simpson Bay as it has been on the east side of the island so you should have good beach conditions.
We will be on the island the last half of October and are looking forward with excitement also.