Can the desk be moved? If so, I'd put it where the table/piano is with the front facing the shelves. Then put the white table under the shelves.

Keep the piano along the wall where it is in the first picture or up against the window.

It doesn't appear as if there is room for a loveseat. You might think about a comfy chair in the corner where the plant is or in front of the window.

You have a lot in the room already. If you could move the piano out, that would be a start.

Is the desk a true corner desk or can it come apart into two rectangles?

Another layout suggestion. Put the coffee station where the plant is. Move the piano under the shelves where the desk is. Flip the desk so the corner part is facing the back wall and the wall that the piano was on. I would only suggest this if you aren't working at your desk all day long. Then you could put a small couch where the piano is now.