Yes, Oppo A5s does have the OTG support.
No. Oppo A5s does not have the 5G network support.
Yes, Oppo A5s does have the support for the face unlock. Besides, it also has a fingerprint sensor.
No. Oppo A5s is not a water-resistant mobile phone.
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.