Blue/Chocolate bedding for sure! Would love that with something like the airplane wall decoration in pic #1 Look around at your other stores for accessories that maybe aren't just "airplaney" Bringing a "pig" piggy bank in with mostly the same colors but maybe one "new" color will all some eclectic look. Check etsy to some wall decals that may give you an idea of what to put on the wall or other things that you may want to incorporate. You can order those or paint something like them...My mother suggested we paint a tree on an empty wall in my baby girls room, so I went on Etsy, and have a tree, some birds, squirrels, nuts, etc. that my parents painted based off the decal. For something else on the walls, I would love to see some basic frames with shapes or letters in a boyish colored plaid inside them. Or maybe check Target for some wall decor "words" in boyish prints/plaids...above my babies crib is "Dream, Dance, LAugh" in girl prints. I put one in the middle on the top row and the other 2 on the bottom row. I thought it would be a lot of words, but love it. I also got one of those book shelves that hang on the wall from Target, but have seen them at PB or landofnod. Pick some books to display in their that coordinate with your colors but don't have airplanes...this will give you a picture that isn't out of place but helps with the overly matchy. A basket of baby blankets or burp blankets will add more pattern and texture to the room. Don't forget Hobby Lobby!

I definitely think grey is great long term- just change out the accessories. But I wouldn't do grey accessories with grey walls. it'll be too blah. Your taste reminded me a lot of the Emily & Merrit collection. Its geared a bit towards girls but there's a ton of great accessories that would work in your room. I adore their yellow and white pinstripe bedding, it would be great if you could find a crib option similar. curtains: https://www.pbteen.com/m/products/emily-and-merritt-circus-stripe-blackout-drape/?pkey=cemily-meritt-collection&isx=0.3.12536 or https://www.potterybarnkids.com/m/products/large-check-panel-boy/?pkey=cboy-window-panels-and-shades&isx=0.0 or https://www.potterybarnkids.com/m/products/stitched-border-panel/?pkey=cboy-window-panels-and-shades&isx=0.0 rugs: https://www.pbteen.com/m/products/emily-and-meritt-circus-stripe-rug/?pkey=cemily-meritt-collection&isx=0.3.10726 or https://www.pbteen.com/m/products/the-emily-and-meritt-tassel-rug/?pkey=cemily-meritt-collection&isx=0.3.11744 or https://www.potterybarnkids.com/m/products/mercer-rug-boy/?pkey=cboys-rugs&isx=0.0

I have no idea! The ceiling appears to be white. The paint underneath was a very light shade of blue. Maybe it's that. The picture you uploaded of the living room is what I was hoping it would be- a refreshing grey.

Best wishes! Nursery are such fun. I would do bigger decals. The ones there now are too small. But, if you want to keep them, I like Is114’s idea of his name, but in letters proportioned to the wall.