Our set-up: Faucet (integrated pull-out sprayer & water control), soap, air gap (required in CA- will be replacing with disposal air switch after inspection), and Instant-Hot at the end. I agree with the other suggestions - consider an instant-hot (we use it way more than I ever thought ... very handy) or the air switch (also very handy, easier than reaching over for the switch on the wall). Good luck!

Thanks for the help! I just spoke to Blanco Customer Service. There are four additional knockouts for accessories. However, it took half a day, lots of internet searching, a couple of phone calls, one to HD and one to Blanco to find this out. I wouldn't even have known to look for the additional knockouts if you GWebbers hadn't led me in that direction! When I kindly suggested to Blanco that they add this on to the description and make it clear to future potential customers that these knockouts are an option, well, she was let's say 'less than grateful'.."ma'am we have that information on our website". Well, perhaps not every customer wants to go back to the manufacturer's website to try and find that out (model numbers are different from what is stated on the HD site, and in fact she gave me the wrong model number at first...) Anyhow, now I know, I thought I was doing Blanco a service letting them know it was not that clear, and it could be helpful to add that to the HD description..." Ma'am that is HD's description" Oh well, you can lead them to water....

What about having a custom filler plate machined out of stainless that would cover the old hole plus go under the new one. Kinda of like the plates that come with faucets that hide the multi-hole configuration if you decide to only do a single. You could creative with it to make it look intentional.

There are plate covers that will stretch across the space and cover the holes. They do look intentional. But they ultimately leave you with a larger surface for mineral deposits to build up, so it's a personal choice if this would be preferable to just using two faucets. https://www.amazon.com/BWE-Chrome-Square-Kitchen-Escutcheon/dp/B01N6JMYQR/ I also prefer a single hole, so would suggest you look for vanity bases without the tops, and buy the top separately, so you can choose your preferred faucet placement.