Interrail is for European residents, Eurail is for non-European residents. So if you’re living in Canada you could get a Eurail pass. Other than the name, they will work mostly the same. So you will see those two names used interchangeably on the interrail community.
If you are just doing those journey, I would double check on trenitalia.com what the regular point-to-point fares would be for your travel dates. In Italy, high-speed trains require a 13€ reservation on top of your pass, slower intercity trains 3€. Only local trains require no reservation. My guess is, that regular tickets will be cheaper than a one country pass for Italy. Maybe also have a look at the trenitalia pass (reservations fees included, but not valid on regional trains) https://www.seat61.com/train-travel-in-italy.htm#trenitalia-pass
If you post your exact travel dates or trains you want to use, we can better help you.