No. Vivo S1 does not have the FM radio support.
Yes, Vivo S1 comes with 18W fast charger in the box and the mobile has fast charging support.
Vivo S1 has a weight of 179 grams.
No. Vivo S1 does not have Qualcomm Snapdragon processor but it has latest the latest MediaTek P65 octa-core processor.