Well, the Compaq dc7900 is like 19+/- years old. That's vintage. It would probably handle basic software as a server. If I remember correctly, the Compaq mobo had a RAM max of 8 gb.
Assuming the Lenova ThinkCenters are of the same era, again, not much you could do with them.
However, since it's a Youth Center, you could set them up with a basic Linux distro and introduce Linux to the youngsters. That might be a worthwhile project.

