He asks: “Will the interloper trauma-inducing time travel involving humanity end when they depart?” What can Creator tell us?

That is correct. As long as they have withdrawn and are no longer present, there will be no time travel excursions intending to worsen Earth directly. That is not to say there will not be time travel done elsewhere in the galaxy that would draw you into a looping of time, done for other agendas, as that is something done frequently by the extraterrestrial civilizations you deal with in the Extraterrestrial Alliance. Each of those civilizations can do time travel and do so routinely for their own selfish reasons. So what this means is that in addition to the time travel for purposes of manipulating humanity, there are time travel repetitions happening galaxywide, including the Earth, done for other programs and agendas of the various extraterrestrial races, and that extends the duration of your lives significantly, as we have outlined. That series of do-overs is contributing karmic consequences from all that happens, and the fact much goes wrong and ends up unhealed means there will be an ever-growing backlog of healing needs that will be ever converging on you as you live your life because the Law of Karma will not overlook anything.