Grouper id say is about 7ish or so maybe a lil bigger. Hes already taken out a picasso trigg that I had. Triggers are pretty cool, I would like one, the picasso I had was awesome while he lasted. Id probably try to find a little bigger this time around though. I def would like a harlequin tusk though, I think he would workout in the setup. I am not sure if the lion will make it to the upgrade or not. His tail fin is losing the webbing, and some "spines" that were there, are falling off, but I think I would get another lion again, as thats the main reason I got into tanks was to get one. are all angels notorious for nipping?
not sure if I want to go to the trouble of fabricating a solid lid though, so I think eels are out of the equation
Too bad about the eel; they're pretty cool fishes. Some of them are less likely to escape than others; my snowflake eel hasn't made any attempts in the year that I've had him despite there being no lid. Angels can be nippers, so I would compare them on a species-by-species basis. Hopefully the lionfish gets better; they're awesome fishes. Harlequin tusks are pretty awesome fish, and they definitely seem capable of holding their own against the grouper; Live Aquaria has larger ones on sale now, too. It might be tricky to get a larger trigger, but it's not impossible. Have you considered grunts & sweetlips by chance?