I found a very strange run, done as Luigi on the Flame Runner. Not sure if I'm overlooking anything, but if I remember correctly Luigi can't use the Flame Runner. There was no video of the run. The run in question: https://www.speedrun.com/run/y976o3nm

Edit: Just found a Yoshi Flame Runner run as well. https://www.speedrun.com/run/zxv7qe8y