Vivo V5s comes with latest Android 6.0 Marshmallow OS which has got Vivo's patented FunTouch 3.0 skin layer. Since the device is newly launched, we do not expect that company will release the new software update immediately.
Yes, Vivo V5s does have support for OTG.
Vivo V5s have 4GB single channel RAM.
No. Vivo V5s is not waterproof.