jzchen, as juvi's they are going to continue to fight since theyre colors are so similar. I'd be surprised if it works out. IMO if you are going to mix a koran and emperor, I'd have the emperor changing or changed to an adult and the koran still a juvi.
rsantangelo3@co, you would think 3 angels would be ok and better then two so not one could single out the other, but that isn't always the case. When I had my queen and emperor, they were literally best buds, swam with each other, never fought, I thought I was going to have the first hybrid queen/emperor haha. My emperor was 4.5" and starting to change, queen was about 3". I added a 6" grey angel to the mix and the emperor did not take to it very well. He builled it around in the begining. Expect some problems off the start, angels will mark/defend their territories. Once that is established, it should cool down and only maybe a little bit of tailfanning/small chase. You don't want to see any crazy biting, blood drawn or wounds. Chasing is completely normal. My emperor would just give a quick "fake" run at the gray when he came near him, the gray would swim away and that was that.
I have seen a large french angel with a medium sized mac angel before. IMO, If your adding a smaller pomo (mac, bluering, asfur, etc) I would add it smaller then the french, but hold the french in the 90g. Let the smaller angel get into the tank first and get established. Plus you don't want to add all your fish at once to the tank, you'll create an ammonia spike. For a third angel, I'd go for a small queen, smaller then the 2nd pomo angel. I've owned both queens and passers (still have the passer and getting a new queen tomorrow) and passers are down right mean! Kirkaz has a small 2" one, harmless. Once they hit 5"+ they are monsters! My is going to probably live in a tank by himself, he's pushing 6" and is currently at my brothers house.
Hope all this helps, nothing is set in stone or guaranted! What other fish will be in the tank? I know you have a PBT, that is an aggressive tang. I'd look into maybe adding a purple tang, different genus but still aggressive enough to hold its own. My brother had a 4-5" aggressive purple tang and I added my passer to the tank who is slightly bigger, within a couple months I had to pull the tang out, nearly died mainly from being bullied so it couldn't eat. And this purple tang is aggressive! Killed other fish. Good luck, let us know what you decide.