No. Vivo S1 does not have the 5G network support. It works on 2G/3G & 4G GSM networks.
Vivo S1 has ARM Mali G72 MP2 dual core GPU.
No. Vivo S1 does not have the FM radio support.
Yes, Vivo S1 has dual 4G support. You can use 2 4G network sim cards at the same time.