It seems like if a user gets banned on their own instance, they show up on this list for everyone (I also see them on my ban list here), so unbanning them on your end probably does nothing.
Seems like just a bug, I think this list should only show local users who are banned, and instead it shows every ban it knows about across the fediverse.
Welcome!
No, we do not do any curation. You can curate the feed yourself by subscribing to communities you're interested in, and changing the front page from "All" to "Subscribed" (you can make Subscribed your default view in your settings: https://lemmy.one/settings)
Yes
https://join-lemmy.org/instances is the only list I'm aware of.
The requirements are not high, although I'm not sure whether ARM is officially supported, so YMMV with an Orange Pi 5.
No