Let the kids plant the seeds in the garden themselves so they have that experience. It's too cold in NY yet to plant cukes. Wait till May. I would put the seedlings you have on a sunny windowsill at school for now. Planting them in your garden will not be good for transplanting later.

I used to be a teacher with a class garden. Good luck. You're doing a nice thing. You might want to plant peas which mature before school is out for the summer.

Agree that direct seeding is by far the best. if you must have cuke transplants start some new ones and pitch these. There is plenty of time still.

Cukes like many other vegetables prefer to avoid transplanting, much less transplanting them twice. Once they develop more than a couple of true leaves, much less begin to bloom, they often tend to stunt if transplanted.

Like Susan said let the kids learn about seeds to plant rather than the artificial method of gardening that uses only transplants.

Dave