The easiest thing would be to take a cabinet door into a paint store and get a color match to paint the walls the same color as the cabinets. You could add shiplap, board and batten or tile it too.

Could you paint the ship lap or board to match the color of the cabinets?

Yes that's what we did. We added the shiplap and painted it ourselves.

Oh, I love that! It looks so great. Thank you!

Yes to Designer's suggestion. No to shiplap.

I wouldn't risk cutting into it, could be plumbing/wiring etc. Designer gave you a very expensive option lol.

@User mine in our last house had both running through it, you said to cut back to flush with the cabinets in your original comment. Erin, I like a beefier island look so I wouldn't lose any depth there.

@User ah I see now I think you mean flush on the sides... gotcha.

If you want something other than the flat back, I think beadboard would work OK (and I love beadboard), but I'd avoid anything with horizontal lines since there seems to be an issue with the floor being level.

Thank you all so much for the input. I like the idea of getting rid of the pony wall and adding board to the front. Will be talking to contractor today.