[Olefin]

And considering the Chinese are fighting for their lives against the Russians I doubt there will be Chinese MBT's crossing the Rio Grande. If the Mexicans do go armor shopping most likely they would be looking at either old French armor or possibly trading oil for MBT's to someone like Cuba or Israel

According to canon their AFV's are almost all ERC-90's, their APC's the VAB

Looking at what they actually had then the most likely place the Mexican Army expanded was they bought more ERC-90's to add to the 120 they already had to produce the AFV's you see that are left by 2001, supplemented by what is left of the M3/M5 tanks (which may have stayed in Mexico and make up the AFV's that are seen in their forces that are still there)

As for APC's using the AMX-VCI in place of the VAB basically conforms to canon - those vehicles came from the Belgian Army in 1994-1996, a sale which might have still occurred due to the age of the vehicles

And yes most of their armor didn't have the ability to stand up to anti-armor weapons that the US had - which again support the canon, which had them basically facing very lightly armed reserve and National Guard units, which may have been equipped more as riot control police and less as infantry ready to fight in a war.