^I havent tried that but I've been dying to, I never thought of cooking avocado until I saw the idea recently and it intrigued me.
Grilling or broiling citrus is supposed to be good too, grapefruit in particular, its supposed to really bring out the sweetness. You do have to be careful about cooking citrus though because if you do it too long it can become bitter, so just enough to bring out some grill marks or just a couple minutes under the broiler (if even that long, I havent actually tried it yet).
Also a warning about the pineapple, cooking it separately and then eating it with something else is fine but you do have to be careful about cooking pineapple with meat because the pineapple can break down the meat and make it almost soggy feeling, so just be sure to cook them separately and then only put them together right before you eat them.
That's what makes pineapple juice such a great marinating ingredient for tough cuts of meat. Anything over 30 mins will break the meat down too much but it should be fine as long as it's less than that. I can see how it would be annoying if you aren't expecting though!