I would cross ceiling rainfall showerhead off the list. They seem like a great, sexy idea. But the reality is that they don't have enough water pressure for shampooing, the water--due to its straight-down direction--is always in your eyes, and unless you are standing directly exactly underneath it, some part of you is cold.

Again, go to your contractors plumbing supply house. That is where all true Pros send their customers. There is no “kit”. It all has to be designed with individual components. And it’s already messed up from what you have said the CONtractor has done.

And you’d better have that waterproofing conversation if you don’t want to be throwing your money away here.

You’re not wanting to do a simple box store tub shower installation. You have a more complex situation involving a multi port valve for multiple outlets. Your contractor has already messed things up by confusing you and ordering incorrect products.

Talk to the actual licensed plumber who is supposed to be doing the job here about doing a multi outlet valve with all of the outlets that you want. And the capacity of your hot water heater to keep up with it.

This is already sideways from multiple issues. What waterproofing system is being used here? Do you want to learn everything the hard way by you having to tear it out in 18 months?

Your contractor bought the wrong thing. That is not how you design an installation with multiple outputs. You have a single valve that switches between the multiple uses. You also need to get the thermostatic valve, not pressure balancing. It is not going to have the capacity for a fast tub fill either because what you want is usually done in a shower only situation. Not a tub shower.

Your professional supply house can help you sort this out. It is unprofessional, to say the least, to tell you to go buy things when you don't have a clue as to what is needed. But, he doesn't either.

A rain shower in a tub is asking for trouble. Water damage and splashing everywhere. Which is why the proper waterproofing Sophie is asking about is so important. As well as the doors to contain the water. Tile and grout are not waterproof. Neither is cement board. You need a separate step.

Your posts contain some red flag questionable descriptions of work that need to be resolved before you let your contractor touch anything else. You need to examine your contractor much closer.

We did something similiar, and I didn't use a bath designer (and clearly I am not experienced) so was figuring it out/purchasing the pieces on my own as well from a bath showroom. Its confusing. And this may or may not be helpful...

We have a shower head, handheld, and tub spout.

On the wall, we have two knobs -- one is a valve that has two handles on it. One turns the water volume, and the other knob (inset on it) controls the temperature.

Then, the second knob is the diverter, and its a 5-way diverter. So the choices are: shower; shower plus handheld (1/2 and 1/2); handheld; handheld plus spout (1/2 and 1/2); spout.

I would assume that whatever brand of diverter/valves are being used, a trim kit of the same brand would be required.

But -- shower head, the shower arm, the spout, the handheld bar...could be any brand.

My contractor's plumber told me to pick out one thermostatic valve trim kit, three volume control trim kits, one for rainhead, on for handheld and one for jets. These were for a walk in shower not tub i am not sure if you should be doing something similar with components. I also was to select the faucet heads and arms. Though I got to pick style and finishes he specifically told me the type of fixtures I needed to select from. He sent me to New England supply where he has an account and discount to select the items. Then he got 3/4 valves and the guts needed to plumb the shower.

My plumber also inspected my water heater to ensure it could handle the amount of hot water needed to fill a different bathroom's large tub and to run multiple shower heads simultaneously in another room. I think that is why Sophie is asking about your water heating capacity.

There are different kids of tub spouts, I think you won’t need one with a diverter in it.