The second promise I'm still working on and so I humbly ask for your help!
I think it's great you try to keep the promise you made to your mom. I live in the US so I can't help a whole lot but does your parents' marriage license, divorce decree, etc. have your dad's personal number, social security number, etc.? Not sure what the Canadian equivalent is. There are PIs who're fairly inexpensive. In the US a couple hundred dollars will give you 24 hours or so of them searching all kinds of data bases, birth certificates, divorce documents, etc, etc. Maybe that's an option?
Wish you good luck.