The proof string should be the same on all platforms. Currently, it's weirdly different on Twitter. In the NIP, specify the string separately, not under each platform.

The NIP should say something about that the string does not need to be exact. All that's required is the npub at the end.

Platform and identify should be in separate fields. It's just cleaner, and allows the identity to have the : character.

And what about nostr? That should have been the first one on the list. 🤣 People with multiple nostr accounts might want to prove that they own them all.