Thanks for sharing, exactly what I was looking for. Like other commenters here, I also think that Lemmy doesn't have to be very popular. But I think reaching ~10k active monthly users would be an essential requirements to have an engaging website.
As for addons, I'm already working on one, called LES (Lemmy Enhancement Suite, similar to RES for Reddit). I'll make it open source in a week I think. Hopefully others can contribute, as I believe one very customizable addon like RES is better than multiple ones.