There are some exceptions to the above statement, even for CX. CX does separate their mileage programme and loyalty (status) programme. For residents of Europe, they can credit the CX mileage to British Airways Executive Club instead of Asia Miles while earning MPC miles/sectors.

Anyway, I do believe that CX tracks revenue on CX metal from other OW passengers, and I do believe that they have exceptions to the op-up priorities - birthdays, anniversaries, and perhaps revenue and miles on CX metal - but likely to be a random event. Those who are elites on other airlines are valuable CX customers too but they most likely are enjoying other benefits from their own programmes. I have friends who are AA EXP, but they fly long-haul J on CX every 2-3 months. I am sure CX recognise them as well.