I think the introduction of the Barash Vow may kill the chance of a new order of Grey Force Wielders being introduced in TLJ though lines like “Light, darkness, the balance” and “It’s so much bigger” along with other things in the canon still makes it a decent possibility. If Rian did go this route he needs to answer when Luke would have gotten back into the fold because I will not accept that Luke is forever abandoning his loved ones to their fate. Whatever they go with I hope these new rules Adam was talking about are absolutely game changing.