Board Thread:Speculation House/@comment-27404492-20170918133425/@comment-14909251-20170926202717

Nikoli, I wasn't suggesting Summer went after Salem alone or that anyone is unaware of her fate, though perhaps their encounter wasn't intentional. Perhaps she was sent to the Black Dragon continent to on a scouting mission to perhaps find Salem and did, but for someone reason couldn't simply retreat. Summer being a Silver-eyed Warrior may mean she was chosen to take part in such a mission precisely because it was dangerous territory where only having someone with that ability could give the mission any chance of success.

As far as the brothers aspect, we are operating under the assumption that they are now occupying human bodies. In other words, the rules of how the brothers were allowed to behave may no longer apply. When and how they can wield any abilities may have changed. Qrow claims they abandoned Remnant, but there is no way to know if that part is really true as he himself is only relaying what Ozpin may have told him. Perhaps they did leave Remnant at some point and then returned because one or both of them were dissatisfied with the outcome.