Carry on allowance

Hi everyone! I’m soon doing YYZ -> YVR -> SYD -> MEL. The YYZ -> SYD flights are run by Air Canada and SYD -> MEL is run by Virgin Australia. I booked it all under one ticket through Air Canada. My question is, since Air Canada doesn’t have a carry on weight limit, what happens with Virgin? Does the unlimited carry on limit carry over? Or will I have to adhere to 7kg throughout the flight? Thank you!!