You can do this quite easily with local bitcoin, as a Venezuelan I have interacted with and sent money with Bitcoin to fiat to Peru, Argentina, Ecuador and the USA, I have also bought Paypal balance and sold an Amazon gift card for BTC as well. I don't think Mexico would make a difference.
Your gateway from fiat to BTC can be local as well or you can use many of the already available platforms :-D
Thank you for you thoughts.