Can you rIse the hallway ceiling height and leave the bedroom heights as mentioned? This is your best solution since the hallway is open to the open concept kitchen...

Yay! I'm so glad it all worked out and you love it. Who cares what people think, as long as you guys love it! You're the ones who have to live in the house anyway haha - pops of colour are great! Do you mind putting up a photo of the room? I'd love to see what you've done with it!

Is your stone veneer to be laid on a slope? I would want to see an example of that beforehand. The stones in a sloped wall are still set horizontally, but the veneer will have joints that look skewed if laid sloped so it could look quite odd.

I am facing the same thing !! In the same spot Your ideas sound fab. I was going to put a door on mine as I don't have pretty books like you have though. But indent the bifold door 300 in, and make it 600 wide as the hole is 900 then have shelves on one side for some treasures I will start to collect cos I have a place now for them. Do you love the arch or are you going to square it off? Do you love the small one on the left? If not...make it a square niche and modernise them / it, as I'm not a big fan but you may love them. What you propose sounds perfect. The dark colour, nice too..or moody wallpaper on the back wall before putting up the shelves.