I think something to keep in mind is that Krueger has stressed players spending a lot of time together to learn each other's habits and know where they'll be on the ice.
So the reason I think we're seeing Olofsson with Eichel right now is that Skinner and Eichel already know each other really well. If Ralph wants to be able to switch Olofsson and Skinner at will as the season goes on, he needs Olofsson to have a good familiarity with Jack so that it works. Then you can slide Olofsson back with Johansson and let them get comfortable while Jack and Jeff do their thing on the top line.