IT'S ALL WORKING
After a week of messing with get the shower plumbed, I have accomplished just that!
The last piece of the puzzle was to install a small pump that would boost our water pressure.
That's the little guy bin the picture above. It does a really great job and boosts our pressure from just a couple pounds to 45-50 with little effort. It uses about 40 watts of electric, so it's even pretty efficient.
My first shower with automatic hot water(via the water heater) pressurized shower was three days ago. AND IT WAS AMAZING!!!!
There's a picture of it and all the plumbing that's been installed so far. I now need to run the plumbing for the washing machine and once we get a kitchen sink, it too. Then the plumbing will be done.