2. How good/bad are AeroMexico frequent flyer miles.
That depends on what's important to you.
The glass half full view is that you can fly out of a good number of US airports for flights to Mexico. Off the top of my head I know that NY, LA, Miami, Chicago, San Fran, Vegas and Houston are all serviced by Aeromexico.
The contrarian view is that Aeromexico miles are not worth much. When I have looked at flights the minimum needed for a roundtrip is 50,000 or higher. That's certainly better than Delta SkyMiles
SkyPesos but it's nothing to get giddy about. Last year I chucked my Aeromexico credit card and solely stick with non-branded travel.