Vivo V5s has Sony IMX376 Exmor RS sensor for the front selfie camera while rear camera is of CMOS BSI sensor.
Vivo V5s runs on Mediatek MT6750 Octa Core processor.
Yes, you can use 2 4g sim cards in this phone.
Not at all. We have used Vivo V5s during our reviews and found that despite using for longer hours, we did not encounter any heating issues.