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.

What a beautiful house, Shahbaaz! I live in a similar house - a 150-year-old colonial bungalow in Kumaon. You have already received lots of excellent advice from better-qualified people, so all I would say is, keep its age and heritage character the central theme. The white tiles do clash, I am afraid ... flooring with terracotta tiles would echo the roof and look lovely. The columns and the arches over the doors and windows are amazing. But I'd say, leave it all chuna-painted - there's a beauty and softness to it. Don't let the painters add too much neel (indigo) in the limewash -- in the hills where I live, they put far too much if I don't watch out and the result is a harsh white. Natural lime has a softer, creamy look.

example: winding staircase, source internet Little modification need to be done for entrance lobby opening, where you could accommodate a shoe rack and the complementary vertical wall can act as a amazing entrance decor wall wall in Kerala style heavy color play or texture/wall cladding with brass mural.. by doing this you get space to mount TV unit and a good space for sofa arrangement (make sure sofas are light as the space is less to accommodate baggy sofas), staircase can be made in the shape shown in sketch plan, with marble finish on the foot steps (or as per interiors), space in the bottom of staircase next to master bedroom wall can be utilized for chest of drawers or a tall furniture, make sure the staircase bottom part to be casted smooth in finish.

that is what i have added if you can see the pic above.. want some suggestions on partition that i can use between dining and sitting