Hey Tiny! If you try using the "search" button, above right, look for "blue spruce", you will find lots of information. Also, try searching on the internet for "blue spruce bonsai". It's always interesting to see what pops up!
You should be able to lift the little trees pretty easily, take as many roots as you can. If you are lifting in the spring, it would maybe be better (?) but if he's going to pull them out anyway...
A wooden grow box is a good choice if you don't have your growing beds made yet. Any well-draining soil will work for the grow box or the bed.... it's less crucial than the soil in a small bonsai pot.
Hopefully you will get other advice too, because I've never dug up spruces, nor grown them, this is general advice meant to help but may be incomplete...
Joanie