No. Oppo A5s is not a water-resistant mobile phone.
No. Oppo A5s does not have the IR (Infrared) sensor.
Yes, you can play PUBG on Oppo A5s. We recommend you to buy 4GB RAM variant of Oppo A5s for the better gaming experience.
Yes, Oppo A5s does have the OTG support.
Yes, Oppo A5s has a dual rear camera set up. The primary rear camera has a resolution of 13MP while the secondary rear camera is of 2MP resolution.