Hi GH, All of that water demand will, most likely require a 3/4" water line, instead of the standard 1/2" water line, be piped to the shower to deliver additional volume and pressure. Without that, you will not have good performance from using multiple sprays, regardless of the valve type or diverter option. And yes, the volume is cut in half with shared functions from a diverter, but depending on the shower heads, may still be adequate. It's a balancing act, and will depend on your water pressure from the street. For a standard 1/2" diverter, to just switch between functions, the Delta R11000 rough-in body is reasonable and good quality. Then you choose the type of trim option and a 6 function cartridge. Otherwise, if 3/4" water line is at the shower, separate volume controls will allow all the functions to flow at full blast.

Just a word of warning on Moen slider bar fixtures...their chrome fixtures the pieces that hold the bar in place are plastic. I made the huge mistake in building of picking out a book and not putting my eyes and hands on the actual fixtures. Not until they were installed and we were moving in (we built from 1300 miles away) that we discovered they were plastic. There was really nothing we could do at that point without changing all the other fixtures in that bathroom, so we sucked it up and lived with it. That is until about two weeks ago in one of the showers the plastic on the bottom failed and the bar fell out of the sleeve! I called Moen and even though it's been over 2 years since purchase they sent a complete replacement. They have completely redesigned the shower bar and while the pieces are still plastic the design is much better and much more sturdy. They have great customer service, their phone system is great. If a CS rep is unavailable you record your number and they give you a time frame in which they will call you back. It's so much better than being on hold forever. Probably way more info than you wanted, but wanted you to be aware.

"The 1st picture on the left has the hot and cold supply lines attached to it? The picture in the middle does not work with the 1st picture?" Correct. The middle picture in your first set of pictures and the last two pictures use a Hansgrohe iBox rough valve. The cartridge, which comes with the trim, determines if it will be pressure balanced or thermostatic. The iBox is what I use. I am not familiar with the showerpipe as I don't like it so have never looked into it. The S/E trim you show does not have a diverter. It would be for a shower only or a tub only. You turn the handle and how far you turn it determines the temperature. The flow stays constant, just the temperature changes. The Metris C trim you show has a diverter so it can have 2 functions. Tub and shower, 2 different types of shower, etc. You turn the top handle to determine where you want the water to come out. You turn the bottom handle to determine the temperature. The flow stays constant, just the temperature changes. The escutcheon is the big round piece that covers the hole. It is part of the trim package. The trim package includes the cartridge, escutcheon, and handles. The cartridge determines if it is pressure balance or thermostatic, and if it diverts or not. The iBox valve itself is the same for any configuration (but it might not use all of the ports, in which case your plumber will cap one off). I don't know what you mean by an integrated volume control, unless you are referring to a thermostatic valve. With a thermostatic valve, you can control the volume of water independent of the temperature. Pressure balance means water is either on or off, no volume control other than that. Thermostatic means any amount of water flow you would like. With thermostatic, you can leave the temperature setting alone so it will always be the temperature you like without having to adjust it (assuming no one else adjusts it). Once again, the shower head and slide bar DO NOT have to be the same brand as the valve. They are independent pieces. You can change them at any time if you don't like what you originally get. It doesn't matter what brand valve you get, you can use any brand of shower head. I actually do not like the hansgrohe wall outlet (used with a hose and slide bar or hook). It looks and feels cheap. Rohl makes a nice one, with an adjustable escutcheon. Delta is a similar setup to the Hansgrohe iBox; it's just not as flexible with installation.

food.....I am getting too old to do so many simple things anymore and that is a far cry from my previous young self, and hiring something so simple to be done is almost impossible and expensive.. It is an expensive showerhead and I will leave it in place as we are old and will probably be selling sometime in the near future. If it is bright, shiney and not from the 1980s, I will let it be and use one of the other two showers, both of which have a simple inexpensive one from Home Depot that I actually do like. I was so disappointed when I went to use that rain head one. I can get wet all over but in no one place enough to make it an enjoyable hot shower or, even to get the soap rinsed away. I want a nice strong flow, not a misty spray of warm water from that tank where I paid to heat the water to a nice comfortable temp. A wonderful hot shower is one thing that I am immensely grateful for and choirs of angels sing in my ears as I enjoy it! I remembrt one time we traveled in Costa Rica where they have a lot of these suicide shower heads that give you , at best, a lukewarm trickle of water. Then, we got to a hotel that had an actual hot water heater and I must have run that tank dry over and over as over joyed as I was to find such a nice hot shower in that country. I am conservative in my use of some things, but my hot shower is one of the greatest pleasures, ever. We had to get a new water heater and we chose an electric one. I am trying to limit my time to about three minutes, but I want wonderful hot water for those minutes.