I think the larger particles are going out of style. They were among the first designs offered in quartz, and that dates back to the early to mid 90s. I seldom see anyone show it as a candidate on the forum. Six years ago when I did my kitchen it was more common. I'd stick with the small particle quartz in the white or the light gray. I like the warm tone of the light gray but it may not have the same undertone of the island, so you'll want to check that carefully. Same with the white colors and your white cabinets.

Start with undermount lights, as wiring might have to go behind the backsplash. I think the 3rd tile on the black sample board goes well with the countertop next to it. And combines nicely with the blue. The swirls/pattern on the photo below is too large and would clash with the woodgrain (in my opinion). White tiles would be too stark.

Ok, look at your in-progress pic. See how that lovely soft bluish-green looks terrific against all that white? That is what you should do -- if not in that color, then some other color (and not grey). All-white kitchen are sterile and boring IMO; white and grey is better but still blah in my eyes. I mean, c'mon -- look how much better this looks than all-white; it's classic but not boring: Or, if you want light counters, something like this soft green (as in your in-progress pics) brings some life to the space: You also have a wide range of countertop choices -- quartz is not the only option; for many (myself included), real stone is the way to go. Lots of choices for black or charcoal granites, quartzites, and soapstone; even marble (but do your homework on stones). Refer to above pic about how smashing black counters and white cabinets can be. You won't get tired of it, and it's not trendy like white-grey veined quartz. ETA: I missed the part about the black island. So in that case, I think a grey backsplash might look quite nice, since you've got a big piece of black there. But still think you could do a soft color on the splash to jazz it up; look closely at the pic above and you'll see they have a dark island and it all ties together beautifully. I'm not a fan of slabs as splash, but that's me -- some people do like it. You may want to consider an interesting granite or quartzite for both the island and perimeter counters (same on both). This is tagged as Fantasy Macabus quartzite, look how great it looks on the black island, and would also go beautifully on the perimeter (and so much richer-looking than wanna-be quartz):

simple white backsplash......color of year is peach fuzz / persimmon. note the blossom color in this...find paint swatches ...stay quite pale but that shade will work w the greens/ grays in counter .....and youre on trend ..... and floor will look good [ a big plus] . a muted version here ...and last pic---- a more vibrant take...