Was There Ever A Medieval Times Episode?

There have definitely been references to Medieval times. In fact I think there was a Medieval related episode either this last season or the season before that. But I think it is more like you said in drawing inspiration from other apps. In the FG game they've done a comic con update despite the fact that it's not directly related to the show.

I hope your wheel speculation is incorrect. I don't know if I can take anymore wheels!