It looks like the floors have been stained/finished to match the cabinets. If you must refinish them (and I would ONLY do this if they ABSOLUTELY need it) I would work with a water based polyurethane. Just as dcarendt has done, going NATURAL with a water based finish will offer a degree of separation which would be JUST ENOUGH to offer some visual interest. Personally I think the COUNTER TOPS need changing more than the floors. My first choice would be a CRISP white (no gray) or a soap stone/slate counter top would be EXTREMELY handsome. You need some CONTRAST in the kitchen. Right now you have mid-tone sitting on mid-tone sitting on mid-tone. You have the lightest version of "brown blahs" I have yet encountered. Changing the counter tops would be faster and probably cheaper than changing the finish of the wood.

I have Mercier, the floors are now 7+ tears old and they are doing great. I regularly get compliments from visitors and neighbors how nice the floors look. One important thing I have done consistently for the entire time is follow Mercier’s cleaning and maintenance instructions, pretty much exactly, which you find in a PDF file on their website. I’ve even sought out and use Mercier brand cleaning solution, which is for their no VOC finishes. Tip: get one spray bottle then get the 1 gallon refill jugs. I also got a vacuum brush head attachment this is soft and intended to not scratch hardwood finishes. Tip #2, I’d follow the manufacturers written/documented/published cleaning instructions before and no matter what an installer tells you to do. The species is American Cherry, which I don’t see as an option with Mercier any more, nor with other peer brands. I have both hardwood and engineered, the engineered was specifically needed in one section that had concrete substrate. I wanted both the engineered and hardwood to look the same and that is what, 7 years ago, set Mercier apart. They were able to supply the grade and finish in one species in both hardwood and engineered. I was skeptical at first but there’s no difference to this day, including in the cherry maturation.

before painting the walls, what kind of furniture are you doing? hopefully blacks/whites, some warm woods, creams, soft greens,,,, I love the exposed brick w/the wood floors. being they are on the warm side, if you want white go with a creamier white. You see how that current blue/gray just doesn't work well w/your brick? it's too cool. how about that light fixture? the boob light never looks good in any room. maybe something like this^, or if you do white walls, consider doing a black trim around the windows. (not the baseboards) this just gives you an idea of how it could look. imagine soft white walls though. (and no ceiling fan!)

You may also find it helpful to consider paint colour from a different perspective. Every grey paint is a knocked-back, greyed-out child colour of an identifiable, fully saturated Hue Parent. That information alone gives you useful detail about a colour. Knowing where within that Hue Family a colour sits can also give you an idea if you are potentially dealing with a colour which may hint more peachy or more greenish for example. And thirdly all the colours you mention are near neutrals and therfore far more susceptible to changes in light quality than their more saturated relatives. All have the potential to shift colour in imbalanced lighting. In order to know how each will behave it’s important to test carefully in your space with your light. See the Colorography Lab at The Land of Color for further info on some of these colours key attributes, so that you might be able to filter out some possibilities before sampling.