You seem to have tiles on your existing ceiling so wood planks would definitely look much better either lightly stained (you'll need to have white wall so that it's not too dark in the room) or painted planks. Don't know what your furniture looks like so can't make any suggestions other than I'd do a different window treatment than what you show on the picture.

Yes definitely might be getting new windows.

I don't know the condition of your windows I meant the way you have the curtains set up.

All white, but visually separate the spaces with rugs ND white beams, over the living room area, and a chandy over dining table. Do not make the ceiling just one surface.