Who will join Sakura and Chaewon in the SOURCENGG

Are there any speculations and rumors about who will be the other members to join the new source group? Could it be unknown trainees or people we have already seen in other groups (izone, ioi) , participants in other survival shows (produce, girls planet)? What do you think? I am so curious

Quote from atropos

Yunjin is rumored to join them. She was a produce contestant from Pledis. A vocalist. The other girls will be new.

Oh really? I really like Yunjin so I hope this rumor is true