Just FYI you can now use a custom addon collection on Firefox Beta for Android, if you want to use a slightly less cutting-edge version. Fennec from F-Droid is another option.
F-droid Fennec has the same whitelist of available extensions as regular Firefox
Yes, but it supports the custom addon collection feature. This way you can use it in a browser that isn't based on the beta/nightly branches, and should be less crashy. I run Fennec to access a few privacy redirect extensions, largely to make reddit and twitter less awful to browse without their respective apps.