Mittlestadt isn't going anywhere anytime soon- he was the primary get for Charlie Coyle. If he is playing poorly next season after a full camp and a set of appropriate linemates, then yeah, it's a problem. Jokiharju is due a new deal, but I also don't believe they acquired him thinking they'll let him walk at the end of the season, and I don't think he's been terrible anyway.
As to the rest, what are you expecting them to show you? Lohrei is being asked to play over his head nightly and he's not been good for the most part. Not worth keeping? Lysell is a playmaker not being put on a line with a legit finisher so he's not producing. Not worth keeping? I want to keep them both.
We'll just have to be on the opposite sides of this one.