I would give between 4-8 weeks notice for the parents. That's what I would do if I ever had to or decide to. It doesn't mean that they will leave immediately but it will take them a few weeks to probably find someone. They might not want to go with the person you recommend but it is a nice idea for you to do that and it will soften the blow.

In regards to the daycare...I would set up the daycare room first and advertise because it will take time to get some bites. Other areas may not be as busy as Toronto. Some of the suburbs are pretty slow and could take months before you get a call. I would get the ad out there, be ready and then unpack while you wait

Good luck