Considering we did a pretty darn similar set of colors, I'll give you some recommendations and photos. Actually, our floors are provincial from Minwax and our all around wall color is Crisp Linen White from Glidden (color matched in Olympic). Here's probably the best photo of just the wall and floor Better shot of the kitchen (except the blurry light gunk on the lens) I would suggest you look at Sea Salt from SW for a muted green/blue, maybe Palladian Blue from BM, we used both of these colors (again matched in Olympic zero VOC) in our upstairs bath. Terrible construction photo, in terrible light, but Palladian blue on outer wall, Sea Salt in the tub area. SS is just a bit lighter and less blue. Palladian Blue main area: Sea Salt around tub (poor lighting, I know):

I'm no color expert, but have you tried BM Wickham gray HC171? We used that in our house and in some lights it reads blue, other times of day a light gray. It might be a good middle ground between your gray and hubby's blue.

I had a very similar looking room with a very similar looking carpet and even the tile at the entry way. A rug would work over the wall to wall carpeting. DO NOT get a cheap polyester one, get a good natural fiber one. I got a great deal on a wool Persian style rug, but a woven wool or heavy cotton one would work too. Not sure about something like sisal, those were out of my price range. Otherwise a cheap olefin/polypro. one like they sell in discount stores will curl on the ends and really, really not stay put and eventually set itself in a non-flat shape you won't be able to hang/stretch back out. I started with one like that, hated it. Have a small area one like that now over our carpet, hate it again. As it is, prepare for constant rug creep no matter what, even if you get a rubbery under pad. Even if you try tacking it down. Best bet is high-end heavy carpet and just readjust every once and a while.

IMO biscuit is a dated color for bathroom or kitchen sinks so maybe post some pics of the other choices already made to give me better idea of why this choice. BTW without seeing the other choices there is no way IMO to even begin to guess wall color