> Can we convert these Lottie things into animated GIFs or something

You might be able to convert them to SMIL (SVG Animations), which is still pretty well supported and does not require any JS dependencies:

https://github.com/bodymovin/bodymovin-to-smil

This is a repo by the original author of the lottie format, it's not super well maintained though, and it only supports limited animation features.