SO6P's brother (HAMURA) will appear since Kaguya has appeared.
This is because I think he might have used his life to seal Kaguya in the Shinju Tree, since Hagoromo and his brother both sealed Juubi and the God tree; knowing that Kaguya's essence was in the Tree, the brother must have done something.
Think about it; Hagoromo is the related to Uchiha and Senju, while his brother is more related to Byakugan (Hyuga) clan and Uzumaki clan, So definitely he must have used a seal to ensure that once Kaguya is out, he (being the ultimate sealer) will also appear to try and reseal her again.
And Kishi has shown us this through Naruto's 9 tails seal and the fourth Hokage reappearance using Uzumaki based sealing.
Also, One thing I know is that Kishi is keeping Obito's body safe because he is either still alive or Kakashi will have to take the two Sharingans to be able to fight, and thus might awaken the Rennigan from there,
or
since Obito is close to death, his eyes might be reacting towards rennigan, so he will open his eyes and call out to Kakashi once more in his time of death and have Sakura implant the eyes to Kakashi and then tell him he is sorry once again.