mommamia- You can put your child into a school that may be the “right” school that looks good for shidduchim, but it doesnt necessarily mean that it is “right” for the child. Everyone looks for someone that is right for them. What is right for one person, isnt what is right for another person. Just concentrate on giving your children the best of what is right for them individually, because with Hashems help, they will find their zivugim easily.
The shidduch process isn’t the easiest and has its own challenges. I personally think that in addition to making sure your children are in the right place for them, you should also prepare them to remember, and try to engrain in your children that HASHEM is the One Who makes the shidduch, and everyone and everything is just a stick in His hands. That they will find their bashert at the RIGHT time, in the RIGHT way, with the RIGHT one. I wish you soo much hatzlacha!