I don't see anything in either code that prohibits it. P2705.1 of the IECC Residential code (2015) doesn't appear to mention it at all, and the UPC 412 (from 2018 at least) is about Urinals (whether or not a shower constitutes a urinal if you pee in the shower is out of scope of the UPC). :) UPC 408.9 mentions it this way: "Control valves and shower heads should be mounted on the sidewall of shower compartments or otherwise arranged so that the water does not discharge at the entrance of the compartment so that so that the bather can adjust the valves before stepping into the shower spray" So nothing to do specifically with the thing pointed at the door, moreso can you turn on the water without being sprayed by it, which is a good idea anyway since that first blast is likely to be quite cold.

I am a homeowner/DIY'er who recently purchased a Moen Eva polished chrome shower faucet trim kit at a greatly discounted price from eFaucet.com along with a CC shower valve and received a pro-grade product un-available to me locally except at a more expensive plumbing supply house that would of charged me a lot closer to list price. Moen sells shower/bath valves with either IPS-Iron Pipe Size, CC-Copper Connection and CC with stops which have built in water shut-off valves that allow servicing of the mixing valve with out shutting off the water throughout the whole house. When shopping at any of the big box stores you will most likely only find shower and bath faucets that are all IPS connections. IPS connections are threaded pipe where as the CC connection valves are soldered copper. In my experience threaded IPS connections are prone to leakage over time and are inferior to soldered copper. Other than the valve connection method the products are identical. The big box stores sell these threaded connection products to their customers primarily because they require little skill to install and that is their market base. Although I could of certainly paid more for a faucet than what I did, I believe there is a diminishing return on investment. Furthermore, if I ever required a part to repair my new faucet in the future, Moen has the parts available to me with lifetime warranty replacement by mail or for more immediate need at the local big box or hardware stores. That option is often limited, unavailable or even unknown regarding many expensive import faucets.

You can do it. He's being lazy because it means more piping. Pressure will have nothing to do with it unless the valves reduce the pressure *a lot*. Not sure how the layout is exactly, but you could run the pipes after the valve up to the ceiling and then down for where the showerhead is. Or run around the perimeter. FWIW, we have 3 showerheads, with two of the valves near the door (and the main showerhead) but one in the back corner for a handshower, near the shower seat. No problems.

i can't see yur plans... our bench seat is on the back wall and one (fixed) showerhead is on the left wall and one (handheld on bar) is on right side of our back wall ~10 inches out from corner. this is perfect for us. i usually use the fixed showerhead.