QX is the airline code for horizon. A horizon flight will never be operated by skywest. Both those airlines do flying for Alaksa. You can always commute as in list as a non rev on horizon and any airline but on horizon you can’t list as a commuter aka you just have lower non rev priority.

the Alaksa commuter priority can be used n sky west flights operated for Alaksa and on alaska airlines flights

yes, any skywest flight that is being operated on behalf of alaska you can list as a commuter and get your commuter non rev priority. The D8Y commuter code is only for a seat in the back.

The jumpseat is first come first serve for alaska pilots on alaska branded flights.
On horizon a horizon pilot will have priority over the jumpseat over a alaska pilot and on skywest a skywest pilot has jumpseat priority over a alaska pilot

regardless if you list as a commuter or not the contract is you need to give yourself 2 flights on any airline to have the commuter clause protections