The new lounge in MEX domestic side is way better than the old international one, at least clean washroom and better food option (a soup, several sandwich, taco, and better drink selection too).

Meanwhile, the lounge in CUN is comparatively miserable, it's a small room with a couple sofas, breakfast only with some muffins, the only advantage of this lounge is they have bottle water that you may grab some.

You may call AM to waive the seat selection fee for emergency exit, but not for the AM plus seat, but you need to call because the system didn't allow to book on website; beside, to call you will need a Sabre AM's reservation code, supposing that your itinerary is booked by KL.

Enjoy CUN, as well as the long immigration waiting in MEX...