Great input sir, makes it a lot better. On it! 

1. Just called it "Key" because that's what Snort etc ask for in the field where you paste it. But you're completely right. 
4. I drew the "cloud sync" option first but it didn't work in my design, in your idea it does, me gusta. 

Btw: I think indeed the way nostr:npub1l2vyh47mk2p0qlsku7hg0vn29faehy9hy34ygaclpn66ukqp3afqutajft sees it, you can skip the bunker-link entirely and just use NIP-05 + password in general.