The Sweet Caroline is really pretty once it's up - I'm using it in my new baby's nursery now I liked it so much. Her room is still in progress (as is the girls' bathroom). I think it would go really in your 6-year old's room with the Betsy comforter, and it's a slightly more "mature" color so might work better with an older child. I have two girls (4 and 5 mos.) - it sounds like we're kind of doing the same thing in terms of linking their rooms. The baby has green (Sweet Caroline), 4 year old has the pink room, and the Jack-and-Jill bathroom in between is a blue-grey color (Sherwin Williams North Star - SW 6246). I did hex tiles on the floor, too, but with black accents. I decided to go a little more neutral with the bathroom since both the girls' rooms are pretty theme-y (once I finally finish them!). Aren't little girls fun?! Between decorating and buying cute clothes, though, I'm going broke, LOL. Shot of bathroom from baby's room closeup of SW North Star next to baby's vanity(mirror frame still needs paint!)

Hmm, I'm not sure about gray walls with the warm granite and dark cabinetry. The undertones of the granite are fighting with that Revere Pewter, IMO. I have used SW Mindful Gray with Giallo Ornamental, but it was tempered by white cabinetry and a lot of natural light. I'm not sure it would work in this case. Accessible Beige might be an option. But honestly? I might try a color rather than adding one more neutral. Your fixtures, mirror frames and granite are really nice and a color might bring them out better.

I would switch sink and those cabinets moving them them to sides with drawer units in center. Yes, I have 12" drawers in my bathroom vanity now ... and the reality is that I have only about 8" of actual storage space. The hardware on each side of the drawer eats up so much of the space. Actually, I'd go with one 27" sink in the middle and a stack of 25-26" drawers on each side ... which would garner you about 21-22" of storage on each side of the sink. And you'd have more counter space. I would put one sconce in center I'd think twice about the double-bulb sconces. Remember that they're set against a mirror, so they're going to feel like FOUR light bulbs. Of course, if they're on a dimmer, you're in complete control. Also, drilling a mirror for a sconce's placement is tricky, and the builder will charge you for that risk. If you were to go with pendant lighting, you'd get the same function with an easier /less expensive install, and it's easy to have the light shine right at "face height". Admittedly, pendants are less traditional. No, no ... moving the drawers to the middle is a good idea, but only if you make them into ONE wide drawer. If they stay teeny drawers, you're still losing all that storage space to the necessary hardware. If you can add the extra recessed lights definitely do so. Be sure these lights are hooked to a different switch. That means you can use JUST the sconces OR both the recessed lights AND the sconces ... after all, sometimes you want to LIGHT UP the room so you can do your make-up or clean, but other times you just want a small, soft light to help you to the toilet at night. Separate switches, especially separate switches on dimmers, give you better control.

I would go all white and then change the shower curtain, art and other accessories to suite them as they grow and change. Let the 5 y.o. help pick out the shower curtain and then build the other accessory colors around what is in the curtain. Cheap frames around the mirror and art can be repainted as their color choices change with a new shower curtain every few years when they tire of the current theme. Here's a link to unicorn art and an art kit that might do wonders for you. https://www.houzz.com/products/query/unicorn-art