Shower faucet with diverter needs replacement but tight access

[T Tov]

Hi I got this shower faucet with diverter which needs replacement but very tight access to see what's going on.
I can't identify the brand....
Currently can open the water to the hose but the top rainfall head leaks lots of water as well.
We can't give the kids a hose shower without getting drenched!
Some questions I have-
1. How do i identify this part?
2. Do i just replace it with a brand name faucet based on the distancefrom the suverter to the main? What do i need to buy?
3. Is it not a DIY project?
4. If I call a plumber do i expect the tiles to be sawed broken?
5. Do i need to buy the new faucet before the plumber comes?

 

[breplum]

Is there drywall on the back side? If so, then it would require a plumber and worth consulting with them on best approach. tile cutting would be likely.
Try google lens with the plate and handles on for i.d.

you can turn house water off and try to remove the cartridges. then try to id them http://barrywalter.com/index.html
But, the diverter would need to be i.d. from a mfr and unless someone can spot the brand, no luck.