Forgot to mention: Solus mentioned that he and Varis likely will not meet again in his timeline, and the ShB trailer mic-drop took place on the first, so I fail to see how Solus (or even Elidibus) will be engaging in some casual mind-control while they're off meddling in our affairs in a different world... Unless 'timeline' doesn't mean "One of us will be dead by the time this is resolved" but more a case of "I'll go have a cup of tea with your 'other' mirror-version on a different shard"... But that's a stretch way too far.