Thanks.. sorry to hear that your yellow eye kole isn't doing well..
When I first introduced my queen angel it was occasionally chased by my yellow and purple tang but it was properly terrorized by my flameback angelfish.. As it was tiny at that time it could hide in places the flameback couldn't get into, one of its favorite hiding places was inside my purple digi conony.. Probably that's how it survived.. At the beginning I did trap the flameback and kept it in the sump for a while but it was still slightly aggressive when I introduced it back..
Now its way bigger than the flameback and slightly bigger than my tangs.. We have peace now..