Now the easy way out would have been to call an architect to figure this out. Yes, a real professional with experience and knowledge of all the building codes known to mankind. And a fee schedule to match. So much for that idea.
Instead Seely cleared areas and used Dollar Store sidewalk chalk to outline the new walls. Then the fixtures that were purchased at a going out of business sale in Houston were placed in the new "rooms." The plumbers explained code and adjustments were made. One sink swapped with another to make the best fit for the spaces. Once Seely and the plumbers were satisfied with the layout, walls went up and plumbing began in earnest. In the end, even the Building Inspector was happy.