Those boards were probably never meant to be exposed as floorboards, but would likely have had a linoleum or rugs or oilcloth for low maintenance. There's no reason not to have them as finished floor now, however, if you can live with the dust-attracting gaps! If they're pine, it's quite hard to get a paint to wear well, because even old pine is a bit soft and scuffs easily. I think if I were you I would finish them with Rubio Monocoat, which now comes in a variety of stains, which you might find wears better than a paint. It's lovely stuff to work with, absolutely no VOCs, and you only need one coat, so although it's expensive there's no waste, you won't be choking and crying on toxic fumes, and you'll be done in a day. Takes a few days to cure completely. I already shared this link once this evening, lol: http://www.monocoat.us/2C-Oil/ They're a lovely company to work with. Lots of informative videos on Youtube, and you can talk to them on the phone as well.

You need a warm color with those beautiful floors. BM White Dove as it is warm and Paper White is cool. I wouldn't use a gray with the floors. Pale Oak could work as well.

The example you provided of the same floor in your neighbor’s place, sanded & finished is definitely still historic and looks good. It’s still the original floor, just a little less rustic/industrial looking (and nicer to your bare feet). The purpose of the building has already changed, it’s not a rice warehouse anymore, after all. You are allowed to make it liveable. You won’t be ruining the history of the place by doing that to the floor.

Why do you want to change the kitchen flooring you have now? I see it in the photo above where you ask about shelving, and in the one with your dog. It looks fine with the adjacent flooring. It will look good with white cabinetry. As to your question about shelving, that is really a kitchen layout question. You can post on the Kitchens Forum asking for layout help for your renovation. But you will need to provide a drawing of the space with measurements. It does not have to be fancy, a handwritten pencil drawing will do, if it has measurements and shows openings. Houzz Kitchens Forum