Hey Sudha ji , I'v a few ideas on the placement , a bed takes 9'x6'3'' so place it on the 15' Wall(you can reduce the width by removing side drawers,then you get 3' extra for bigger wardrobes on both sides) with one wardrobe on each side one for him and one for yourself and a chest of Drawers to keep other stuff handy and two Ottomans or love seat in front of the bed so you have enough space in front of the bed for traffic as well,and on the front wall to the bed place your Wall hung T.V, PLEASE keep the colours light , use white marsh by Asian Paints or Honey dew , here are some pics .

If you can't clean up the painted edge, you could always add a 1x3 piece of wood as molding. You can even carry it up to the ceiling to frame that wallpaper. I don't see that paint color in the wallpaper, or maybe it's a lighter version of the flower centers. Maybe stencil on a design using the darker color, or another color from the wallpaper to help tie it together. Then narrow floating shelves or vertical frames or something in the painted areas it you feel you need it. Maybe turn the bed around so the wallpaper is the headboard.

add a mirror in each niche, use a nice wallpaper behind it and simple curtain blinds will make it interesting. Use a highlight paint on ceiling to match with wallpaper

that's right. a column like this is not a handicap at all. it's not too deep, so it does not take up much space. As kalatmak space has suggested, one of its uses would be to place a cove light. you can also extend a shallow shelf of the same depth above the bed to place tiny led lights below it and light up the wall behind. then you can also do a false wall extension behind to place the bed against it and create a little niche above the bed head. you could paint that niche in a different colour