My vote is color on the left though I have no idea about the finish. I would also suggest you get that color painted on a sample because those light tones can look way too light IRL. :)

I like the color on the left too.

None of those suggested finishes will actually stand up around water. None. You need a far tougher professionally applied industrial wood coating film forming finish like a Renner in a 5 -25 sheen. No knife work should happen on any counter that is waterproofed enough for sink use. Only a mineral oil finish for knife work, and never with a sink in it. So pick one or the other use.

Depending on the desired sink depth and how thick the butcherblock is, a topmount sink may be more comfortable to use. As well as being more insurance against water damage.

As to the posted colors, I would prefer lighter and less grayed colors. IMO, a more pure color w/out the grayed tone with look much, much better with walnut.