I just actually wrote this and actually used it in my actual compiler:
(map (lambda (body) (fold-left replace-operator body uvar* lbl*)) body*)
fold-left is reduce. You guys, for all my talk, I don't think I've ever actually used this for, you know, fixing an actual bug before. But I actually thought of it and it actually solves exactly the problem that I needed it to solve. I'm blown away.