I suggest that you bring an infant carseat(carrier)with you. If there is a vacant seat, you can just leave your baby in the carseat. When I brought my baby home at her 4th month, she slept most of time in the carseat, there was no problem for having meals or going washroom.
If you are going back in later April, there are probably not many vacancies since the students are going home also, you can ask help from either the air crew or your neighbour passager or someone who would hold the baby for a while.
It is better to have a stroller with you especially in the airport. You don't need to worry about the luggages if you fly back to China. You will see them in China airport. When you return to Ottawa, you need to pick up your checked luggages to domestic entrance. Just pay tips to the port services, they will help with luggages and your transfer to Ottawa.
Don't worry, you should be fine. Do not hesitate to ask for help. People are very glad to help a new mom.