Hi Mike,
this is a real cool school project.
you can find some information about the supported valves in the opensprinkler blog. https://opensprinkler.com/blog/
if you have the original opensprinkler hardware you can use every 24V AC and DC valve. The valve have to be open if connected with 24V. thats it.
If you want: Post your chosen valves here and we can check it.