While I have no proof I always wondered if the Ghostbloods were the ones who actually sent Helaran and that it wasn’t the Skybreakers who sent him after Amaram. It seems much more like something they would do and also Amaram suspect’s Thaidakar. Maybe Helaran was both a Skybreaker initiate and a member of the Ghostbloods. We do hear Mraize tell Shallan her being a radiant doesn’t mean she can’t join them.