Dont know if this helps but my kitchen island is greenish gray, bm providence olive and my walls and trim are sw Alabaster White.

Smart thinking on your part since there are more hues of white than any other color. And boy can that bite you if you bring two whites with different hues togeather. Ask installer if they have a scrap of quartz from your counter. With scrap in hand,go to tile shop where you can lay various tile and grout on quartz. Without a piece of original quartz,your best option is see if the tile shop will loan a rear seat load of samples to bring home. I reccomend this wherther you go with white or colored back splash. It's weird how a color can change when another color is brought alongside. Since colors aren't true on a computer screen,I didn't go to your link to make reccomendations. Also take into consideration,it's easier to atain good results by combining complementary colors than harmonizing colors when both have to be chosen without side by side trial. .

psd,,,here's your white w/a similar wall colorlooks nice w/a darker wall color too. You could always do the white shutters and then a black window casing. basically this w/your white shutters. can't find a pic. people do dark wood shutters all the time, black wouldn't be much different. I found these in gray. btw, here is the black photo shopped in that room this looks great w/all of the window and crown molding. very traditional looking.

You don't say why you are planning to cover the windows. Are you wanting privacy? Plantation shutters of any color are not going to improve the look or the lack of light here. First, see about having an arborist come and improve the trees outside. See what might be done to lighten the color of the deck roof so it can reflect some light. Then tackle the interior lighting with LED's and more sources of light. Any window treatments should help soften the heavy masculine feeling of the woodwork, which is beautiful. Shutters won't do that.