M1's to Mexico?

No they did not. Story closed.

How long did the M1's last compared to the MP54's?

M1's were sent to just outside of Mexico City per contract with Bombardier. They actually had a "rider" escort the cars to Mexico.

MP54's lasted the longest due to M1's initially being restricted(plus MP72's and MP 75's) from the Flatbush Ave. Terminal.