On your paint problem I can't be much help. This usually happens because of damp -- please get a damp expert to make sure that there isn't any damp lurking in your walls. I had this once when I had pipes leaking inside the walls. I didn't know that. The other alternative is something like painting before the plaster is dry or some kind of chemical mismatch. I do know you will have to scrape all the mucky powdery stuff away and start again, at least on those areas. Don't try to seal and prime and repaint until you know exactly what the problem is and how to fix it.

I think all white will be a very nice scheme and the differences in the white will just add subtle difference. In the above pic the walls are more white than the table, but mixing with the light tan colours and greyish tones makes this gradient of whitish tones work well.This room is all white as well with the furniture and walls, but adding the punch of the other colours masks if the whites are slightly different as the bright colours become the focus. The walls in the pic below 'read' a very pale grey so that would be an option, just ensure that it is a whitish-grey and not muddy or warm. I would choose the sofa colour as your main colour and accents to match from there.

Not necessary to use only paint for the change. There are different applications like wall papers, textured particle board, wooden panels etc. It actually depends on who is using the room. For the changed looks, go for wall paper on one wall and color selection as per the age of the user.

Various area serves various purpose in a house, thus they have their own requirements. The ambience and character of every space could be unique yet in sync with the overall design of the house. Flooring plays a major roll in developing the character and mood of a space, so i would suggest to get a professional help (as there are various layers of detailing which adds on to the interior subconsciously) and work with them to identify what works for you according to your need, preference & lifestyle. Regards, Priyank Mangalam Principal Architect Meraki-PMA