Pooty tang, I'm glad with the Idol getting fat.
Trigger and Idol ? never kept both together but you already have a hepatus tang, idol and a flavescens... and want to add a trigger ? what is your size again ? 125g right ? and you want to add a regal angelfish ?
either you have a uber skimmer and filtration system or that is quite a bioload
not counting the small stuff.
now triggers are ( depending on which ones ) either mild agressive, agressive or complete maniacs.
plus they get big, grow fast and add a ton to the bioload of an aquarium.
they are easy to keep and feed though.
isnt that a reef tank you have ? they are hit or miss with corals ( stony ones ) but they are very MISS with inverts : snails, shrimps, etc, they will be eaten. that's why they have those jaws....
you already have a touchy fish : idol. there shoudnlt be any compatibility problem with the idol at all, but the trigger is very roudy ( well, you get the point ) whilst the idol is shy and timid.
your idol is doing well , or yo say so.
if it was me, I would skip the trigger