Niger triggers tend to be pretty peaceful, but triggers and lionfish tend not to work out well. I would decide one, maybe two fish that are requirements for you, then add from there. Most of the moray species will do fine with either a lion or a trigger, pass on a tesselata though. Undulated morays are sweet and a really good sized eel for a 180, but most go ballistic and eat anything they're in with so I would pass on those as well if you're looking for more of a community.
If you want a clown trigger, they can do very well in a reef setting with smaller fish that they can't catch, but in a 180 I wouldn't mix in any other predators. Look up "Darryl" on Reef2Reef, he's got some great tips on keeping the more aggressive triggerfish in community settings. He's kept 4 clown triggers in reefs, if I remember correctly.
Orectolobus reticulatus and Orectolobus wardi are two smaller wobbegong species that occasionally show up, if you're interested in sharks at all. Not many other species I'd be comfortable keeping in a 180 full time, although there are a few catsharks that should fit the bill.