FWIW, before I got my NEXUS card I always have myself three hours at YYZ... And I'm not a fan of arriving early to the airport.
It's not abnormal for a 1 hour customs line followed by a 1 hour security line (though I'd assume a J seat will get her into the AMEX Platinum security line).
The J seat probably gets her MLL access too, just in case the lines aren't long.