There are many roof systems out there, you have to see what is the industry standard for roof construction in India. You can take a look at this Website to get an idea what roof construction practices they use/d for that region. This is one of more up-to-date concrete roof structure.

You need to mention your budget for us to advise a suitable method of which there are countless. Whatever may be the method we try, in retrospect it would only be secondary to real concrete and therefore would lack the solid raw monilithic almost indestructible character. The second reference image looks like a tile. The first image is a textured wall which can be achieved in several methods and quite obviously the price will go north the more you try to get closer to the real thing i.e raw concrete. Look up Dulux concrete effect as an easy method. In any case in our country the easiest method would be to use fibre cement boards and engage a wall texturing specialist to create the concrete texture as in the first ref image.

living/dining/kitchen it's an open layout like in one of the images. the ceiling is uneven so we are planning to get it fixed with re-plastering. I might not be able to get a skilled painter in my budget to get the textures right, so I thought by just applying a coat of cement I wouldn't need a very skilled worker and also get the industrial look.

It would be better if you can consult Admixtures company like ., Myk laticrete, Bostik ., etc It's a kind of plaster STUCCO...