The way I have always seen NightMist's incap side is that she has been sealed away in some realm, possibly the one GloomWeaver is sealed away in.
I can totally list off the ways I have seen each Incap side of every hero, i'll do them in order by the alphabet.
Absolute Zero: Inside his Cyro Chamber there is a system failure and he is trying to reach his suit. That one is fairly obvious though. Possibly Miss Information work?
Absolute Zero Elemental Wrath: I see this one as he surrounded himself in complete ice as he may be near death and it was the only chance he had to try and keep himself alive until someone can get him out of the later. Maybe even trapping a enemy inside it with him?
Argent Adept: Something religious possibly? I'm not up to date with my crosses, so I can't say much about this one.
Bunker: Getting really shot up be someone, not sure for Expat attacks him for whatever reason or there is a mysterious villian at work. Also the amount of dents put into probably means he was fighting someone really strong, so maybe Fright Train?
Bunker Engine of War: Fright Train still seeing himself as a villian in his reflection. Maybe the reflection even talks to him and tries to sway him back to the path of evil?
Chrono-Ranger: Simply stuck in time and can't find a way out. Looks pretty boring there as well.
Expatriette: It looks to be the first confrontation against her mother Citizen Dawn. As she doesn't have an eye patch yet and it looks fairly fresh. Dawn even paints the Rise in Expat's blood above her.
Fanatic: Staked to a wall and looks to have flames infront of her. Most likely Apostate has her trapped and is revealing about how he created her or whatever it was he likes telling her.
Redeemer Fanatic: The outcome of another battle, possibly one with Apostate? Looking at her mask it doesn't look like her face is going to be in good shape afterwards, that's if she survives.
Haka: Stuck inbetween a rock and a hard place. Not really sure what else to pull from it.
Eternal Haka: Library was destroyed and now he is alone without shelter in the Final Wasteland.
Legacy: Legacy post death, Young Legacy hugging him as he dies.
Young Legacy: Legacy holding his dead daughter, realizing that the Legacy line is at its end.
Mr. Fixer: I forgot what the line traslates to, but i think it refers to his death.
NightMist: As above.
Omnitron-X: Omnitron has removed the empathy chip from Omni-X and has now joined Omnitron. As if one crazed machine wasn't enough.
Ra: His staff is broken in his hand and doesn't look to be the happiest. Fighting a losing battle against the Ennead.
Ra Horus: All his training was useless. Still lost to his foes and this time they aren't letting him live.
The Scholar: I know very little about alchemy, but i'm guessing something isn't right here. Maybe over use of the stone has done something to him?
Tachyon: Two villians have her on the run and trapped. Making her speed useless against them. It's an interesting set of villians though, one ice and one wind. It's almost as if it's villian versions of Absolute Zero and Tempest. The both also look to be female, the wind one for sure is female.
Team Leader Tachyon: She used to be a hero, then she took a bulley to the knee (yeah I went there) from Ambuscade it looks like.What good is Iron Legacy if Ambuscade is still running around?
Tempest: After arriving on planet Namek he battles it out against Voss, while Young Legacy and Unity makes it off with the Sentinels Balls to wish all their friends back to like. Will Legacy make it in time to save everyone and achieve the legendary Super Parsons? Tempest loses his arm in the process, but at least he can grow it back... Oh... nevermind, getting two different thins mixed up here.
Tempest Sacrifice: This is what happens when you take your enemy far away from civilization. Especially when you need to be around water near constantly to even survive.
Unity: Captured, maybe by F.I.L.T.E.R. to conduct experiments to probably learn more about how super powers are gained? I really don't like those guys if that's the case.
Unity Golem: It's either before Unity becomes a golem and who ever is behind this is trying to make a Unity, possibly bring her back? Or afterwards where someone is taking her apart because they are sick and twisted...
Visionary: Dark Visionary is slowly sapping away at Visionary's mind, trying to make it's way in to take complete control over her.
Dark Visionary: Visionary is being completely lost inside Dark Visionary, she now has complete control and will never be the same again.
Wraith: Probably a Batman reference, but seeing as I don't read comics to often and don't know. I've always thought it was Wraith dieing inside and she was going to start doing things not so legally to get villians. Not nearly as bad as Legacy though...
Rook City Wraith: Beaten by her four Batman inspired villians. How scary!
Wraith Price of Freedom: Spite breaks the Wraith! The one comic book reference I did get.
That's about it, most were more descriptions then what I take out of them, but most were obvious and others not so much.