The issue with Alitalia is that their carry on limit is just 8KG for ALL carry-on with only one piece allowed.

Air Canada allows for two pieces of Carry On at 10KG + 10KG. They're quite lenient.

Knowing that, I would likely have to check some carry-on which will add time. That will likely add a ton of time at FCO.

If we have to gate-check, I know it is VERY expensive with Alitalia.