Lead Developer of Swarm here.
1) A bit ago, we changed from having a split between our publisher accounts and our user accounts. Many developers already had both accounts (pub/user) and were merged. Publishers that didn't have a user account were automatically given one, which is what you're seeing there. Email us (admin@swarmconnect.com) and let us know what username you'd like, and we can manually switch it for you :)
2) We don't currently support display strings in the leaderboards, sorry.