Not that I know of unfortunately. It’s been a while since I’ve been on iOS so I may be wrong, but I believe all browsers in iOS are actually webkit under the hood (what safari runs on). So any fork of Firefox for iOS would also be just that, quite different from desktop or Android Firefox. I did hear the due to some rule changes Mozilla may be working on a non webkit version of Firefox for iOS but that remains to be seen

Yes, it does. It allows you to log into your Firefox account. Ive been doing it and it syncs just like the official app

This is true, but I encourage people to check out either mull browser or fennec. Both forks of Firefox on Android with privacy enhancements, the ability to use any Firefox store addon (this may be in release now I am not 100% sure) and access to about:config. I’ve not found stability issues with them either

I’ve been using fennec as my main browser for a long while now and it’s great

Stable frame rate at ideally 30 or above where quality is such where it is reasonable to tell what is going on. Doesn’t need to be pretty. But if it’s incomprehensible, or stuttery, I won’t play it on my deck