We have three triggers together in a 125. In the order of size:
Raz=Pinktail
Spaz=Undy
Taz=Picasso
Pink, when we rescued him, was in a tank with a shark, puffer, and two other fish, all were HUGE. The Pic was in a tank with my favorite Damsel (that the lfs owner let get eaten up-he is now out of business, thank goodness) and a couple other fish.
The Pink had been returned 2 times, and the Pic just got along. We watched both of these fish for several months before we purchased them. They got along with all their tankmates, in close quarters.
Anyway, on the point of the Picasso, we were lucky and got one that has the attitude, "Buzz off, leave me alone, you don't scare me" toward the Undy.
As far as your inverts, fagetaboutit!!! They all may be different temperments with other fish, but the inverts, all triggers with go for. We have button polyps and shrooms that they don't bother at all. We had a crab that was in a shell the size of a baseball..............bye, bye!!! We got 150 crabs to help with cleanup..........I think we have........oh.......maybe a dozen left.
I don't know what I was trying to get across in this post, other than, try your HumuHumu and see what happens. They ARE cute little buggers when they are tiny. We saw some teeny weeny ones at an lfs in FLA.
I like mine and he is so gentle with me I can almost pet him.
Try it.............good luck.
.............Later