About 20k are probably from hexbear, which migrated from their own distant fork of lemmy to the current version, so now they show up in a lot of trackers. They still haven't enabled federation yet though.
I hadn't even heard of Lemmy until a few days ago. Maybe it'll ride the momentum. End of the month there will probably be another influx, considering the reddit changes.
Let's hope so! Some of the communities are a bit empty still. Hopefully it'll change. :)
I can't imagine being that unlucky with your instances, maybe you're running into bugs or the less intuitive parts of Lemmy (like how links to posts and communities don't work how you'd expect them to)