1. Kinda depends upon what you are looking for. Obviously, Your unit will be large enough that you could potentially throw a small party in there. You could also try and stake out one of the grill and picnic table areas and maybe try to do something small and simple there as well....
If you are wanting something a BIT more private, you could look at renting a pool cabana or 2 where you could store some goodies.
There are a couple restaurants at the Wyndham Grand you might be able to have a birthday dinner at.
For more money, you could look into some of the meeting space or suites at the Grande for something providing more space and privacy. There may also be a way to obtain and reserve some space within the activity centers [or space in the main building used by the sales department, like their theater] for a small gathering. You would need to talk to the resort itself though to see if they can help arrange anything.
It really depends upon what kind of party you are looking for. something small and intimate with just your family and kids? something bigger and more private with a large number of attendees?
foodwise.... There is the onsite pizza which will deliver to your unit (or I'm betting a cabana). There are also a couple pool bars around the resort that have things like burgers, sandwiches, wraps, etc and might be able to help provide food for your party. Again, you may want to contact the resort to see what they might be able to do for you.
2. I don't know for certain what the plans are for this summer, but I know that in years past they have offered some outdoor movies at the resort. You might be able to contact the resort's Activites Desk to see if they are planning on doing the movies again this summer or not.