I bought an old house built in the early 1960’s and although I plan to renovate the bathroom, I’m not ready yet, but I have a more immediate issue to resolve. Recently, the hot water valve has not been fully shutting off the water. No matter how tight I close it, there is a small steady drip, so it needs replacing. Complicating matters, the last time I called a plumber, I was told that modern building codes in my area prevent them from replacing a faucet like this with another two-handle setup. Instead, they would have to install one of those with a single hot/cold handle as these are considered safe.

Well, as you can tell from the photo, the tile and caulk is already in need of repair. Fortunately, I’m skilled with tile, but I don’t want to pay someone to install a whole different kind of bathtub faucet and shower only to have to follow up with my own renovations after the fact. Plus, it’s expensive, so it seems like I’ll have to do this myself.

With that said, my question is, what kind of parts do I need for this? The part connecting to the faucet has a number of 23078 printed on it. Is that a serial number or some kind of specification? As for the handles and faucet itself, I had no problem locating something similar on Amazon. However, it’s unclear to me- given that it’s only the handle at issue, what would I need to replace it at minimum? Do I need both the front parts and back parts? What is the specification I should look for?

So, we are redoing our bathroom and my wife found a sink that she really loves, but our current sink has one faucet for both hot and cold and the new one has two faucets. Is it hard to convert from one to two? I'm assuming that there is just some sort of divider piece, but I don't know much at all about plumbing. I tried looking on Google, but I don't know the proper way to search for it. I just want to know what I'm getting myself into before purchasing it. Any tips or articles that can help me out?

Edit- Picture of the sink https://imgur.com/cJ6GBzz