They'll do.
Power supply wise, take your pick. You can either build one yourself by buying a toiroid transformer, a bridge rectifier, and big capacitor(s), or look for one of the pre-built switched mode (rectangular metal box) ones that outputs around 48V. Either will work, and of the top of my head, if you were to use the 3 drives to their full capability, then a minimum of 6 amp output would be needed, but I'd doubt the motors will need that much.

If you're doing a complete box, then you'll need things like connectors, switches, terminal blocks, and possibly a few indicator lamps. Also a good selection of cable will help.
Control boxes aren't really a one-size fits all thing, as different people prefer different things and will do the same thing different ways, however for basics, you need to consider your options for the following main items-
-E-stop system
-Power Supply(s)
-Motor Connections
-Computer interface
-Additional features (jog buttons, probe connections...etc)

I've not got time right now to explain those items further, but if nobody else posts up, I'll expand on them later.