When I was there in October, they said all GOLD and DIAMOND can use lounge. (this is different than in previous years, but all DIAMONDS will get lounge access). Lounge is very nice, good food, servers that serve and help.

I think you can also have breakfast in the restaurant, if you want, it is a very nice breakfast buffet.

As for upgrade, email ahead of time with your preference (ie: view, suite, ect...), I have found the staff very helpful. I have been at the hotel a dozen times all on award stays. They have always gone out of their way to be friendly and helpful. Enjoy your stay.