A soft, warm grey shade would look lovely, and can be as dark or light as you want. A warmer shade will work with the brown stained wood floor, and the grey will complement the black granite. You could have an undertone of green, blue or tan if you didn't want a pure grey. And it would look nice with any silver metal hardware, either polished or satin/brushed, so you could choose pewter, chrome or nickel. It would still work with white trim too.

I would not have a partition. It is just one more thing to clean, and adds a sense of clutter to the open space. I'd arrange sofa to face away from the kitchen, though. The sofa will then be facing the terrace garden, too.

And how about durability as a flooring option? I mean .. What is the expectancy of its shine, gel layer and life in general? In a nutshell is it a viable option for living room floor? And if yes, then would its edges match or would it still be like tiles where edges don't quite match?

This is a fabulous room. It oozes a bygone charm that you would lose by adding false ceilings and tube lights. Please don't! Go all out to preserve this magnificent floor and the beautiful furniture. That mirror is superb, as is the old painting. Keep the wall colour as is and change the upholstery after polishing and keeping the beautiful wooden furniture. The upholstery is mismatchedat present. But the different styled armchairs look very comfortable. Keep them. No modern furniture will give you such comfort. When you re upholster, refrain from choosing firm foam and such nonsense. It is far better to have good quality down or cotton, which moulds to the body shape. Invest in a high quality traditional patterned Persian or Kashmiri carpet for a restrained stroke of colour. Your upholstery should pick up colours from this carpet. So should the curtains. Please never even consider vinyl blinds, horizontal and vertical. If you tamper with this room and remodel it to be 'modern'- you will lose a treasure.