Yes OK, thanks for clarifying... the wallet with passphrase is independent... still accessible even if the wallet without passphrase is recovered/stolen.
Yes. The victim's wallet is not compromised as long as the thief do not have access to the passphrase. But it is good to use a strong passhrase that would be difficult to brute force.
The possibility of brute force is the main problem here. If your seed is compromised you should move your coins as fast as possible. The passphrase can give you the time that is necessary to do that. If you dont move your coins then your password can be brute forced now or in a few month. You can never know and will loose your coins at some point.