Autoptimize is compatible with all themes & plugins, just not always out of the box pulloverschaf, in which case you can configure AO to fix any problem that might present itself as per the FAQ 🙂
Specifically for Avada; as this is a premium theme I can’t simply download & test it. I’ll be happy to assist with any troubleshooting if you’d encounter problems as I did for others.
have fun,
frank