No. Vivo S1 does not have Qualcomm Snapdragon processor but it has latest the latest MediaTek P65 octa-core processor.
Vivo S1 has ARM Mali G72 MP2 dual core GPU.
Yes, Vivo S1 has a dedicated MicroSD card slot. You can use 2 sim cards and a memory card at the same time.
Vivo S1 has a weight of 179 grams.