I have just copied the wallet files, so this makes me a bit worried. I think the wallet files enough, but I hope to get this confirmed.
I got the more expansive list for backups from a Jim618 post I found somewhere and printed back in November. It mentioned that exporting private keys doesn't save transaction labels; and that what I show (for single wallet backup) is how "..to backup EVERYTHING for a wallet.." We'll wait together for the captains of this ship to respond.