Doesn’t anyone think it is odd that after 17 years latter after Greg left that Regina wanted a baby which is when Emma was 17 and had Henry? Was it added to the curse that Rumple knew that Emma would have a son and it is funny it took Regina 17 years to realize what she needed to fill the hole?
I also think Rumple was able to help get Henry, because he had taken Snow’s and David’s hair to create the lovecurse so I am sure that is how he kept track of Emma.