Shumakov on the second line, ahead of Oshie? Gersich on the third line ahead of Eller? These are the spots you'd put them in if you're absolutely dedicated to their success, but also if you needed them with the big club right away. I'd argue that Shumakov, if he makes the team, deserves to skate a few games on the top line because the guys there speak his language, but that's his only claim to an immediate top six chance. Backstrom and Oshie play fine together, so why mess with it? Oshie has one 30 goal season to his name, and he played most of that year with Backstrom. Yes, they were also on Ovechkin's line, but Ovechkin got back up from 33 to 49 goals last year playing with Kuznetsov, and again, if it ain't broke, don't fix it. Gersich is going to be an NHL player in a couple years but this year he's waiver exempt, and Eller was 5th among Caps forwards in playoff points (
https://www.nhl.com/capitals/stats/playoffs). Gersich has an NHL point, too, and I respect that, but let's not get carried away. He's going to Hershey to play top six minutes, bulk up, work on defense, and score his first professional goal or twenty.
Bowey ahead of Djoos? Maybe with a strong training camp. Too close to call.
Breaking up Orlov and Niskanen would surprise me.
If Connolly plays fourth line, happily, and extends at 1.5M, great. But there's also a chance that demoting him after he was 8th among Caps forwards in playoff points, to give top nine ice time to a bunch of kids who weren't part of the championship, kinda hurts his morale and causes him to test free agency. Is Brett Connolly replaceable? Sure. But can you be sure that one of Gersich/Shumakov replaces him within a year or two? Nah. Can you be sure you can replace BC at a lower cap hit? Also no. In a salary cap league, he's someone you offer an extension to, at 1.75, for a couple more years, and then reevaluate. Maybe by Christmas you come up to 2M/yr and him choose a term between 3 and 5 years.
Not looking to get locked into 6 or 8 yet, based on two years of 15 goals, but is he the kind of 3R the Caps win the Stanley Cup with? Yes. So far he's the only kind of 3R they win with, so they might as well try some patience and see if they can't help him take the next steps and break twenty. It might be as simple as giving the second power play unit more chances. If they can put Kempny on that unit, so they can create cap space and roster space for Lucas Johansen next summer, it'll really help them long term. The only reasons not to give a second power play unit almost equal time are that they might demand more money and that Ovechkin needs to score lots of goals to keep the team in the headlines, which helps generate revenue. To the first objection, signing one of BC or AB to an extension of more years without a significant raise would answer it, now that Eller, Wilson, Orlov, Kempny, and Niskanen are locked up through their useful careers.
To the second point, it's worth having a good statistician check whether there's a limit of diminishing returns on Ovechkin's ice time per game. I know some guys like Lemieux or Messier just seemed to get better the more they played, even upwards of thirty minutes a night, but most mere mortals are more effective in short shifts, with some rest in between to get their breath.