Yup present both tickets at check-in at YUL, and they'll be attached, your bag checked through, and your BP's issued all the way to FCO.
You might even have a case to get the YYZ AIF refunded down to the $4 "connecting" level rather than the $25 departing fee by sending in both tickets to refund services after the flight with an appropriate explanation.
Last edited by pitz; Aug 19, 2018 at 1:26 pm