I’m wondering if the OP is willing to consider other airlines. If the only choices are UA and CA, then the alternate, besides the choices mentioned above, would be: the OP could leave from XMN the next day, enabling the OP to leave in the morning.

What I would do: given the above conditions, and presuming the OP doesn't want to stay in XMN, I would fly to HKG in the afternoon or early evening. A quick check of hkairport.com for today (02 Apr) shows flights from XMN arriving at 16:30 (KA), 19:20 (MF), and 21:20 (KA).

Then I would take the midnight flight to ICN on OZ, and when I arrive at ICN around 5am, I’ll have a variety of connections for my selection. This solution allows me to: 1) avoid CA, 2) avoid an overnight, and 3) stick with Star Alliance.

Good luck!