The problem with The Cloister is the heat and humidity that part of the year. I have been this time of the year and I must say it felt like a sauna. If the heat isn't an issue, its a beautiful resort. I know your bias Stars as your from Georgia.
The same goes for the Caribbean/Bahamas. Weather this time of year tends to be stormy and rainy....and yes its the hurricane season.
The plus about Nantucket( The Wauwinet) is the weather is cooler. Its a great venue for a wedding.
You may fair better at the One and Only Ocean Club on Nassau in August as the hurricanes paths tend to be further south.
Good Luck,
Will