Do the soap dispenser it will be fine, plus you will save counter space not having a bottle of soap on it. I had an extra hole in my sink and we did the same thing, put in a soap dispense, and it is fine. It doesn't take up a lot of space either... Maybe you could have a customer hand towel holder made to screw in to that hole on the right if you don't like the soap dispenser... You could find someone that does custom metal work, like railings, or balcony railings. They may be able to whip something up for you, like a pole with a loop on top or a horse shoe shape to hold the hand towel. I wish I had one next to my sink in the bathroom! I also think you can get a metal cap filler for capping off holes in a counter top that are not being used by the faucet. Maybe later you can buy a different faucet.

Those levers can orientate left right or forward. You can set up the fixture so the handle protrudes into the sink.

Alternatively you can make it an air switch for your hairdryer/straightner/shaver.