I have a AT flight from DSS-CMN (Y) and then >12 hours during the day on the ground before QR to DOH (J) (and then onward) booked through AA. No issues accessing the flights on QR and AT sites, but AT wants >50 EUR for a non-middle seat.

No OW status but United 1K (*G).

First question: Is there any way to get a free assigned seat on the AT leg? I know I can status match, but don't want to burn that bullet unless I have to.

Second question: Can I leave a checked bag at CMN without retrieving for that 12+ hour layover?

Third question: Will I have Zenith lounge access on both arrival and departure? (I assume yes since I could theoretically spend the whole layover in the airport)