No. Vivo V5s is not waterproof.
Vivo V5s has 3000 mAh battery which is non-removable. It offers talktime of upto 12 hours on 3G networks and standby time of about 270 hours.
Yes, you can use 2 4g sim cards in this phone.
Vivo V5s is not much heavy. Despite of having 5.5 Inch display and bigger battery, the phone weighs just about 154 grams.