Jessi Dowling 【ツ】's Profile

Looking at all your furniture I think you should paint your living room a cool color like this green I found on this English website http://www.dulux.co.uk/servlet/ColourAvailabilityHandler?name=green_parrot_3
It's called Parrot Green 3.
It's calming, not to 'in your face'
A perfect color for your living room.
Also you asked 'Should I paint all the walls?'
I would say, no. On your 4th picture you have a picture of a big window with two walls either side. Paint them to walls and then paint the rest white.
Your other question was 'Would you paint the picture rail?' Paint it white like the other walls.
I hope I helped you!