Mexico is a unique circuit, in that air density is approximately 22% lower than for a track at sea level. This affects many things, that in turn had an impact on the amount of penalties flying around during the grand prix weekend, the first of which is downforce levels.
Teams will, as normal, simulate the optimum downforce level to achieve the best lap time, and then make decisions on the wing and drag levels. At Mexico City, the wing will have a larger cross section than you would normally have to generate this level of downforce, with most teams probably running something similar to what they run for the Hungaroring.
With the turbo hybrid engines, power loss is not a problem at altitude, it's just that the turbo will have to work a bit harder and run faster to achieve the same boost levels. But beyond that, the main problem for the power unit is cooling, so most teams had larger, more dedicated radiator cooling ducts.