Gwelu's instance are only because his child kinda barged in into his streaming place and it's still audio only. This is the same with say, Hana Macchia's american dad, Henry, who is also voice only. Aside of that, ex-ID Etna and Bobon also have their family member (sister for Etna, lil bro for Bobon) collabing at one point on their own stream, and there's a clip where NijiJP Lize Helesta got a message from Ange Katrina's mom.
It all shared the same thing. Voice Only. (There might be others that I don't know, so I might be wrong here)
The reason there's the whole 'lmao we got scammed' is because it's a handcam stream and maybe people was like 'oh boy enna gonna let another hand that isn't hers into the camera??' and then boom it's just a baby-shaped toy.