Thank you roj leather and Simon for your recommendations. I like the hanging chair and the almanda creeper on the wall. This will certainly liven up the patio.

Thank you all for your reply ,much appreciated. Since the size is rectangular I feel more of modern look. I would love to have a Victorian or a classy look though. Also I am allowed to construct roughly around 1800 to 1900 sqft. The plot entry is from the width(10sqmtr) side, so some more restriction. I am from Mumbai (India ) , the climate here is kind of extreme.Though the coolest can go max to 10 degree Celsius and the hottest can go max 45 degree Celsius. This will be my dream place where I would like to call in friends and family, though there is no pool , I would like to have a plunge pool kind of at the rooftop.A small sitting lounge to entertain guest. Sine it a small size , I am limited to doing all this stuff mostly at the roof top. Please advice.Thank you

Eventually when you come to resell, a pool is an added plus. But for your own purposes, emptying the pool and adding a deck over it with a hinged door and steps placed below would be great for storage (as per option b but bearing in mind you could revert). All the best for your lovely new home.

Consider composite decking material which are more durable.