Could a group of lay volunteers build interior office space to code?
You can also do the electrical.  Much of it anyway. 

Commercial electrical usually is required to be in conduit, and usually, there's a civil requirement that commercial work be done under the supervision of a real electrician. 

You don't need to be an electrician to plan circuits, figure out routes and rough wire lengths, develop a wiring plan and get him to check it over. 

You don't need to be an electrician to have all the right parts in all the right places. 

EMT conduit is pretty straightforward to lay.  You don't need to be an electrician to lay conduit, since  you're not putting any wires into it. 

You also don't need to be an electrician to pre-fish a pulling string through each segment of conduit. 

Now the electrician attaches the wires to the pulling string, and that usually tedious job is in his rearview. 

Another thing you don't need an electrician for is buying supplies, particularly 11-13 colors of wire.  Electricians are inclined to use a rainbow of colors if they have them, and they always have white, black, green and red.  Buying other colors - brown orange yellow pink blue violet gray (lots of gray) and white-with-red-stripe and white-with-blue-stripe, will allow him to more easily color-code his work for easier maintenance later.