Welcome to Cork, you will love it here. This site (https://www.[citizensinformation.ie/](https://www.citizensinformation.ie/en/education/primary_and_post_primary_education/going_to_primary_school/primary_education_life_event.html)) is your one stop shop for all Government related questions.
So if you son turns 4 this year he can start school, but doesn't have to. So if keeping him at home for another year is helpful and takes the pressure off you can. If it isn't you can get in touch with schools to see if they will take him, I suggest phoning them, but many may be full. They will be able to suggest alternatives though. https://www.education.ie/en/find-a-school
Daft is the best place to find a place to rent, but like someone else said if you wander into the agents and ask them to keep an eye out for you many will. It's easier for them to have someone ready and waiting for a house than having to go to the trouble of advertising it. I've noticed that agents have houses up on their own business websites before Daft sometimes too.