Yes, it is still at Kona. If you get there, look at a bar menu and you don't see it, then ask the bartender. It has at least two kinds of rum in it. Maybe three. Honestly it's just rum, orange juice and sour mix served in a pineapple.
Yes, you can get one to go. It's not served in glass, so you can carry it away with you.
I think the liquor license allows you to carry it around the resort. If you wanted to take it on the monorail I don't see how they could stop you, but I think you're technically supposed to hang around the resort. It's kind of an awkward thing to carry around with you though. You are correct in saying that you won't be able to carry it into a park.