Rumplemom:
I don't think that you said when your trip will be.
During the "high" season, there ARE chairs and umbrellas to rent at the beach. They're kind of pricey, as I recall. We bring our own. I've even heard of people who buy their own at
WalMart and just leave them at the beach or at the resort, if they don't have room to take them home! But, of course, the rentals are much nicer.
I don't know the exact dates of when the lifeguards are on duty. Again, that will depend on your trip, too.
I don't recall any place that rents boogie boards. I know there's a small store in Palmetto Dunes (along the route to the beach house) that SELLS them, but I don't know if they rent them. Again, there's a Super WalMart on the island, where you can get them relatively inexpensively, in case you don't have room to bring them home with you.
There is not food service to your spot on the beach. We have done all your options at one time or another -- gone back up to the beach house (Signals), brought our own, or returned to the villa. There are lots of options!
There IS shade at the beach house, other than at the eating area. Again, depending on when you go, it can sometimes be kind of crowded there.
I would definitely recommend bringing a cooler -- as far as the rest of it goes, if you have room for it, you'll probably be able to make use of it; if not, you can figure out what you need when you get there!