Great space and style! It's hard to tell in the photo but are your countertops white? If so, I would do the "comfortable" chair option in white. You could also do something similar to this:

Maybe incorporate the black into the dining area through a chandelier instead.

FYI those are not comfortable the strings cut into bare legs IMO you buy for comfort first and I like the black it works well with the table.

If you're looking for something that's, as you stated, "messy, kid friendly," we would recommend the cheapest option, full plastic, from Industry West. Black is good enough to go with that dining table.

I would suggest formica chairs online. You either choose that 1960's retro look or modern.

Wayfair ,Target, or Ikea. Google formica chairs

go with comfort & black..