These are the colour scheme you can go with ,Highlight the staircase with dark colour with muted mild colour background.Muted colours will bring down the boldness of the projections and merge down its presence.

Can you provide some photos of the exterior?

Hi umesh - Here are a few photo wall ideas that can inspire you: https://www.houzz.in/magazine/design-a-family-photo-wall-stsetivw-vs~77445238

Hi, There are a number of ways in which the area under a staircase can be utilized. In case of a cramped house or space restrictions, this space can be used for providing storage, services or even a powder room as elaborated below : In case there are no space constraints and all the other areas are taken care of, the space below the stairs can be used for add ons such as a library, study, cellar or a minibar. In case there are any dogs in the house, this area serves as a spacious and compact kennel too : Apart from this, if the space is to be treated solely considering aesthetics, it can be livened up using a bit of indoor landscaping, sculptures and water body : Since, you have a db on the left wall you can use these ideas accordingly so as to not take away from its accessibility and utility. Using wallpaper or tall planters or a painting may prove useful in that case. Hope these ideas help. Do let us know what you decided to choose. All the best! Regards, RnD Atelier Nagpur