When it comes to corals it will depend on what type of Trigger, the Angel I would question with the corals.
Triggers love Nori so you could hang Nori in the tank for your trigger, I just hand feed my trigger Nori daily, I offer my Pinktail a Long Strip of Nori and my Trigger eats it like a piece of spaghetti.
Sponge would be great for the Angel to pick at on your LR
, you can buy a Frozen Angel food that has sponge in it.
It depends on the size of your tank when it comes to both of these fish........