If the cabinets have a factory finish I would hesitate to paint them as the paint will not be as durable and the white is pretty. Maybe just paint the island and change to quartz or granite counters.

I would wait until you move in to do anything. With a few colorful things on the counters, you might decide that's all the "pop of color" that the room needs.

I've learned from personal experience that it's good to actually live in a place before undertaking renovation unless you have a very firm idea of what you want. It's hard to make suggestions when we don't know anything about colors/design style that you like. Just off the top of my head I'd suggest painting only the island if you want color, navy is very hot right now, grey is still popular, but almost any color will work with your white. I'd also minimally remove the 4 inch portion of backsplash, that's good for the bath but not the kitchen. Counter selections are endless! If you like modern you can get concrete, if you love marble (my fav) but don't want the maintenance there are lots of quartz imitators, quartzite is beautiful, soapstone too. Your tile backsplash selection will be highly dependent upon the counter material. Definitely deep six the pendants. They all look too similar, something larger in scale for over your table will break up that line. On the plus side, you have a truly beautiful base for your tweaks! Wishing you the best in this endeavor.

Sorry, another thing or two - I'd change the sink faucet to something really pretty since it's on display and new cabinet/drawer hardware (love unlacquered brass with navy/white or grey/white, check out Forge Hardware for fun stuff).

Love the neutrality!!!! Use accents that can go away when you tire of them...get some stools, rug runner, area rug, and furniture that will look good there. Do nothing to change any of it for a while... it is awesome! You do not have to have granite or quartz... spend that money feathering your nest in other places in the house! Good luck!