Floating shelves will not hold a lot of weight without extensive (invisible) support, and you will need bookends on each one. They will also look much, much cheaper than what you have.

You could order custom built-in bookcases and sell the dark wood ones. Paint-grade wood is cheaper than stain-grade.

Why don't you paint the shelves? They look like they are well made and sturdy. You could put gathered sheers inside the glass doors to hide what is inside so the overall look isn't too busy. If you use a really good primer you can get an excellent finish. Just takes a bit of work.

the photos aren't very clear in showing the room.