What is best way to plumb a rainshower head, handheld,and tub filler?

Seems I have two options:

pressure or thermosatic valve with diverter (to tub filler) stacked with a two way diverter to the shower heads

Or the pressure valve without diverter stacked with a 3 way valve....this one sounds like extra plumbing?

Will pressure or thermo work best for setup...we now have a PB valve.

If I turn on water to sink and flush toilet there is a drop in pressure to sink. I think I read somewhere that this may mean I'm better off with a thermo?? Hansgrohe does have a PB valve with a volume control.

This is a small master bath redo for house built in 60's.

Thank you for any help...this is an awesome forum

JoAnne