Far as I can tell, no. I'm open to adding an emacs profile to Saka Key. It's as easy as modifying this JSON file: https://github.com/lusakasa/saka-key/blob/master/src/options...

I don't think so. But there's this which allows you to "remote control" FF from Emacs: https://github.com/cute-jumper/emacs-firefox-controller