Man, a 180 is a great size tank. You could do a full size nasty Jag alone in that tank for life, and if you're lucky, you might even get him to tolerate a female in there with him. A pair of Jags with others -- I don't think so.
A single Jag in that tank with a few other species, if he grew up with some other fish, it MIGHT work out for life, might not--depends on the Jag. You'd just have to try it and see. All same sex would be your best bet.
Mi/Devil in that tank would fit size wise, but it could go nuts one day, too. Then it might not--you'd have to try. they're very much like a Jag in my opinion. I really think that full bred true Citrinellum, or Hoga's, or Amarillo's are a little less crazy than a Labiatus or a cross with a Labiatus. So If I tried an Amph with other fish in a 180, I'd do a Hoga, or an Amarillo.
But......if you were to maybe come off the Jag or Midevil idea, you could do some Vieja in that tank, thin them out as they grow real big, and end up with 3 maybe 4 big full size Vieja for life? That'd be MUCH more likely to work out in my opinion than a Jag or Midevil community thing. You may not like Vieja, or you just really want a Jag, I don't know. But at least consider it.
so in order of likelihood to really work out long term imho......
1. Single Wet Pet Jag, Midevil, or maybe a big Trimac--that'd work for sure.
2. 3-4 Vieja in that tank, no Jag or Amph--I think that'd be VERY likely to work long term.
3. Breeding pair of Jag's, Midevil, Trimac--you might lose the female, might not, but you'd at least end up with option 1 if you did lose the female.
4. Jag or Midevil in a community with some other big SA/CA cichlids. It COULD work, but something could very well just go psycho at 10-12 inches and you'd lose fish, or be dividing the tank up into 2-3 parts.
I think 3 and 4 are probably equally likely to work/not work.