Here is the best answer to all your questions that I can give. The size of the room is going to be 18x16. The receiver that I currently bought is Yamaha RX-V683. This home theatre is currently going to be in India. So the prices of the speakers are more than twice the cost in the US which is the reason I'm having some budget constraints. The front speakers 610F alone is costing around $800 (Converting to USD) and the current system including all speakers and receiver is costing close to $2450 (Converting to USD) (Spending the same amount the US can probably get me a much better selection of speakers. Probably a 7.1 with Atmos?). The largest main speakers that I could do is the 610F. But if something else comes at that price, I'm willing to do it. Again posting my current speaker selections here
R-610F FLOORSTANDING SPEAKER for the front left and right speakers
RC-62 ii for the center speaker
R-41M as the surround speakers
R-120SW as the subwoofer
Receiver: Yamaha RX-V683BL
Thanks a lot, @billybob for your active responses