I should have searched the forum; the freezing question has been asked before here. how to freeze the leaves
I don't think it was answered but I can't find a reliable source. If I were going to try it, I'd use a roasting pan to blanch for a couple of minutes then plunge in ice water to set the color. Dry them off, fold/cut, then freeze. (Unless you're using small leaves or have a huge freezer, you'd have no choice but to fold/cut.
I used fig leaves to wrap fish then bake it; I know you can grill it also. They added a slightly sweet taste--reminds me of how I thought they smelled would taste--in a way. Others describe it as coconutty. I never tried using them in place of grape leaves in dolmas; if I had some, I'd consider making a small test batch. Could you eat the "case"? Sure. Would you want to? They're not poisonous but might be tough. Worst case is you eat the insides only.
I was thinking about using banana leaves to make tamales. Again, I should have searched here for information. Banana leaves in cooking
(Hey, in my defense those threads are 6 years old!)