>>103844177
>>103855579
Since the hashtag implies a Live
It's probably this series of events at SPWN
2019 from 19th November to 17th December
https://spwn.jp/events/191119-watanukisanchino
https://spwn.jp/events/191128-watanukisanchino
https://spwn.jp/events/191203-watanukisanchino
https://spwn.jp/events/191212-watanukisanchino
https://spwn.jp/events/191217-watanukisanchino

The repeated signatures are
top-right Sora
bottom-left Hibiki Aoi
bottom-right Sarugakucho Futaba

The individual ones are
top-left Tenjin Kotone
top-center Oozora Subaru
top-right Asano Ruri
bottom-left Natsuiro Matsuri
bottom-center Mononobe Alice