I've seen a bathtub set up the way you want. It had a standard tub faucet down low to service the tub (and in your case you could add a hand shower diverter), and a second faucet set up high to service the shower head. The upper one wouldn't need a diverter, as it would feed straight to the shower head, just like in a shower-only stall. This should be fairly simple to plumb since the wall will be open anyway. The concerns I would have would be if your code authority would want you to use larger water pipes because there are two sets of fixtures. They might also, or instead, want a larger size drain. I wouldn't think these would be required, but, you jurisdiction/inspector might vary. An additional option for you on the lower filler would be to use a standard 3 handle valve set (middle being the diverter valve) and instead of sending the output to an upper shower it just go to a stubbed out pipe where you could attach the handshower.

Yes, you can add a hand shower by adding a diverter as shown in the link below. I have 2 moen hand showers with the slide bar and have been very happy with them. No problems so far......going on 6 years. Here is a link that might be useful: hand showers/diverter

Auntjen, when I get out of the shower, Zephyr rushes over to lick any water on my legs or feet. Rather than waste water till it warms up in the bathroom, I catch it in bowls and pour into buckets in the shower (used later in the garden). The minute I turn on the water, both cats come running to drink from the buckets or dip their paws in. High excitement!

The leak is only out of the faucet. It is not behind the wall so we do not need to rip out tile and start again. But, you make an astute and important point about finding ones that fit in the space that is currently there. The current ones are Gerber. Old and cheap. Our plumber warned against Price Pfister saying they are pretty cheap and have lots of service calls. Yes, there is an access panel in back. There is currently no shut off valve so when they install the new set they will also install turn off valves too. Our guest bathroom has this same tub faucet combo by Gerber. We are going to replace both at the same time.