Eric:
I suggest mapping out what you want to accomplish before getting a plumber involved. Otherwise, the plumber is likely to think in terms of their past experience - which more than likely does not include darkroom work. I also like the idea of bring hot and cold water out, then have all the connections exposed (as in Jerold's darkroom). Allows you to change later.
Jerold:
Having recently corrected (or at least identified) some electrical errors by the licensed electricians doing the kitchen remodel, it might be worth verifying the GFI status. Just trip any or all GFIs and verify that there is no power to the darkroom outlets.
Also, I see that you have separate filters for hot and cold water and that all your water outlets are downstream of the temp controller (at least that's the way it looks). If the outlets are, in fact, downstream of the temp controller, is there an advantage in doing separate filters? I'm building a new darkroom and had planned to use one.