Here are the walls:

No

You CAN, there's no rules saying otherwise, but I think it would detract from your cool windows. I'd leave that space bare.

Drapes or Curtains would soften the look. No to low pictures.

no. In my house, they would be covered in dog drool.

It would be nice to see the whole space but no to art below those windows. You could do some fabric roman shades for color and pattern if you wanted to.

Here is the full space

What a cool space

@localeater amazing ideas, I never thought of the glass shelves.

I want to put small tiles of my favorite things and inspirational quotes on the wall behind the sofa. So maybe small mix tiles will do the trick.

Thanks for the suggestions :)

You don't have a lot of room, but I might skip things on the wall there and put a very narrow sofa table back there with a modern lamp and a few decorative items. You could lean some art or put it on a little easel.

Is there room for art on the tv wall? I'd put plants on the window ledge.

I was thinking of turning this into a travel wall

Use command strips and hang the art on the windows.