If you search on Google flights, you can find mixed Alaska / United itineraries that will pull up for purchase on United.com.

In particular, I was looking at one round-trip combo that had AS as the departing flight and UA returning (SFO to PSP and back). A few questions:

• Since I'm buying from United.com, will this issue on 016 United ticket stock? Normally with OTAs I'm used to the ticket being the marketing carrier of the first flight (or first intl flight, but this is domestic).
• What happens if I try to change or cancel on United? Do I retain the full $$ amount credit that can be used to change to anything United will sell?
• The fare rules for the first leg are giving me pause with text like, "A COMPLETELY UNUSED ITINERARY THAT CONTAINS ONLY RESTRICTED FARES ANY RESIDUAL AMOUNT MAY BE ISSUED IN THE FORM OF A CREDIT CERTIFICATE WHICH CAN BE APPLIED TOWARDS FUTURE TRAVEL ON ALASKA AIRLINES AND AIRLINES FLYING UNDER ALASKA AIRLINES CAPACITY AGREEMENT - HORIZON AIR OPERATED FLIGHTS / SKYWEST OPERATED FLIGHTS." Does that mean if I try to change this itinerary, it behaves like two one ways with different airlines? $$ paid to United overall splits into some credit which can only be used for more AS flights and some of which can be used for UA?

Thanks.