The thing is that I don't think you need a much better player than either Marino or Pettersson for the 2nd pair. I think a MP-Schultz 2nd pair is perfectly good enough, while Petry and Krug are way better than Schultz. I like the Dillon idea because you're getting a better version of what Johnson is supposed to be, plus you have the ability to run with MP-Riikola on your 3rd pair.
Need? Maybe not.
Want? Yes. Having two pairings like a 2nd pairing is nice in the bottom 4, but its not as nice as having two pairings verging on being 1st pairings in the top 4.
And either JJ has got magically better and doesn't need replacing, or Marino can carry a pretty average player into being a strong bottom pairing guy anyway. You don't need a 4m guy on the bottom pairing with Marino there. Also, wait, are you saying Dillon-Marino is the second pairing?
With Lehner and Varlamov both getting $5 million last off-season, I think $5 million for Markstrom is a very fair estimation. Same thing with what Howard got, and I think Kuemper really isn't that different from Markstrom either. I think the $5 million area is pretty standard for average starting goalies, so I don't think Markstrom at $5 million is exactly a ridiculous suggestion. He's a very consistent .910-.915 starting goalie, I don't think he's good enough to get a huge payday in free agency. Especially considering what Varlamov got last year and how saturated the goalie market is right now.
Prices keep going up. A 5m standard one season becomes a 5.5m or 6m standard very quickly - particularly when last off-season was unusual with the last minute massively lower cap estimate (we all know a lot of players went for less than expected, right?).
And while there are a lot of impending goalie UFAs...
Holtby - Good
Crawford - Probably finished.
Lehner - Good
Anderson - Probably either not good or finished
Howard - Probably either not good or finished
Markstrom - Good
Greiss - 33's a hell of an age to break out from being a good platoon guy/mediocre starter
Halak - 34 but ditto
Talbot - Probably not good
Khudobin - Backup
Etc.etc. There's three proven starters available. There's a lot of ageing gambles, I'm sure one will reward whoever signs them, but not much reliable quality. I don't think that should count as saturated.
And sure, maybe Markstrom or whoever would sign here at 5m. But I wouldn't count on it. He could almost certainly get more elsewhere.
No because I think Kahun can do that too. And who they'd be able to get that wouldn't cause problems, I think it's Kahun. And the "serious roster problems" come when you're limited at having JJ or a JJ priced player as your only addition to the defense, which can easily be argued isn't good enough from the defense.
You have a fair bit more faith in Kahun than I do, both as a player in general and a fit for Malkin. And see above for why I'm not that fussed by a JJ/JJ-priced player on the defence (and given your post pointing out Marino-JJ's excellent numbers, are you really that fussed yourself?) and even if I was, I'd regard the 2nd line as more important than the 3rd pairing, and even if I wanted to give riches to both, I'd start shaving a well paid RFA off the third line before touching the 2nd if it looked great. That's if, of course. No guarantee.