I haven’t really seen a consensus term for lemmy users analogous to ‘redditor’ or ‘redditors’.

I don’t think lemmy is ever likely to overtake reddit in terms of userbase size.

There is a lot of overlap among communities, since there are multiple hosts available.

If you ever used Apollo on iOS, then you might enjoy the Voyager client for lemmy. I know it’s available for iOS but I don’t know about android.