Yes, Mexico has a trade agreement with Mercosur. Mexico has duty free access to Mercosur countries but there are offsets beyond specific quotas intended to maintain rough trade balance. That is why I've logically linked buying, for example, Sigma Lithium or other suppliers to export to Mexico so maintain rough balance and assure preferred access. Mercedes Benz, GM and Stellantis(the EU parts) have all used those to great effect as have Boeing and countless others. Elon and other Tesla/SpaceX people have been discussing these issues with Brazil (far more than half of Mercosur) for some time.
In Brazil there is active BEV development and use, albeit small, although there are bus and truck BEV factories and one BEV car in production with plans for several more this year and next from several Eu and Chinese companies. In major cities charging infrastructure is growing rapidly. I, for example, mostly charge my Volvo in shopping centers, and at home if I haven't spent enough time elsewhere.
In Brazil there are also significant tax incentives for BEV, at State level, but including the largest markets of SP, RJ and MG.
The Northern South America countries and Central American countries have no significant auto markets or manufacturing base, All of them are accessible but infrastructure for BEV would be from a base of zero.
