No. Vivo S1 does not have auto call recording. But you can use Apps available on the Google Play Store.
No. Vivo S1 is not a waterproof mobile phone. However, plenty of covers available for the mobile which can protect from sudden water splash.
No. Vivo S1 does not have the front camera flash. It has a display-screen flash.
No. Vivo S1 does not have the IR remote sensor.