Painting interior doors properly is much tougher than most people think, especially if you want a professional finish. Interior doors are mostly painted in a higher gloss or semi-gloss finish which is less forgiving than the eggshell paint used for walls.
To ensure better adhesion of paint, increase durability and protection for walls.

Mr Paritosh, I am not sure about actual application of PVC in this case. I have seen people using acrylic panels on wall ,not PVC. I am not sure what material & application you are talking about. Please talk to some expert, I think you should apply coat of primer or some chemical on brick wall before covering it with finish material directly. This is not proven option, so you will need to experiment & see how it goes. Between idea sounds interesting – save on plastering & paneling. We did one room where client wanted one wall to remain as brick wall. We did primer on it, it was left as highlighter. Such experimental ideas are risk prone. In most cases they do not last for years. Either they dont stay functional or you stop liking it.
One more thing to keep in mind is that the lowest estimate is rarely the best deal. That's because the quality of materials and workmanship is generally inferior. A competent, responsible contractor will never sacrifice quality for cost savings.