When we went last July, we were on the dining plan and they would not substitute onion rings for the FF. We paid OOP for those. We did get the shakes for a drink, and now that someone has mentioned it, adults only. But they let my 8 year old order an ice tea, and he was able to have "my" shake.
Onion rings were very good. I try to take a picture of all our meals, and by the time I got my camera out of the case, there was only one left!