Well said tempestb. Regarding the address identifiers, I've brought it up to Hiro and this was his response.

"To prove that you own an address you would sign something using your private key for that address. It can then be unencrypted using the public key (address) which everyone can see. There is a sign and verify feature already in the wallets for those who want proof that someone owns an address."

So we may already have that feature. To be honest I didn't even know of it, but will look into it now.