Hogfish?
 

Will a hogfish eventually eat large hermits,urchins,lobster?

What type of Hogfish? I had 2 candy hogfish(they were paired) they never bothered any inverts or crustaceans. But when it came down to other fish they were total *** Holes. Well one was mean and the other was peaceful so I gave the mean one to Kien and kept the nice one. The one Kien has now is friendly and doesn't bother anybody that i know of in his new home, and the one i kept also doesn't bother anybody they mind there own business they were both about 2 inches long.

It's a Spanish they get big and it's not paired

Hello I personally have had no experience with these Hogs but when Scuba diving i have seen them pick up large crabs and small lobsters and swallow them hole. so i would assume they are not reef safe.

I Had a dianna Hog given to me. It ate all my shrimp and small hermit crabs

Ok no worries thanks for the info
What about the urchins ?

I believe they eat Coraline algae but don't quote me on that. Theres tonnes of different ones that may and may not