I have not tested Mobile-Friendly-Firefox with these browsers yet, as I am waiting for official arm64 releases before installing them onto my Librem 5. While I think that everything should work, anyone can share issues here on the fediverse, on my Mobile-Friendly-Firefox repo, or on my forum thread. I'll try to check all three from time to time so I don't miss anything.
Minor Update:
Added to install and uninstall scripts
Support for Librewolf flatpak
I have tested and confirmed that it works perfectly.