Custom Shower Plumbing Question

'Hi, I am currently building a custom shower in my house. I am planning 2 standard shower heads and one rain head. there are so many options out there that im having trouble deciding how to control it all. i have considered one thermastatic valve and 3 volume valves but i am having trouble finding anything that isnt incredibly expensive. i have also thought maybe using standard single knob controls for each of the shower heads, then "T" off of the shower heads to run the rain head with an on/off valve. my goal is to be able to be able to control each shower head independently and then have the rain head added in with one or both shower heads.

while typing this my wife came across 3 way diverter valves. would i still need a temperature valve with something like that?