There's a couple things that help in these scenarios, and a 45G cube is definitely not one factor on your side.
Frequent feedings, multiple hosts, and enough places to swim away from aggression are the 3 things to come to mind, at the moment. Where are you on beefing up filtration and what's the exit strategy if and when you notice aggression?
Didnt see this...
So he has his old tank as a back up if they need to get split, worst case scenario if it does not work out i have a 150 gal 6 foot, i can take some off his hands.
I really dont expect an issue with most of them except the black ones since they are bigger.
I already have him set up with a auto feeder that can feed 4 times daily while he is at work.
Lid to prevent anyone from jumping out.
and if he needs to add some more rock to create caves that should help for any needed hiding spots...
Everyone and their mother told me i could not house the angels i have together, at one point i had Emperor, majestic and blue face... no issues...
A little agression at first from Majestic to blue face but after a few months that has changed.
If anything because she has calmed down it encouraged the blue face to come out more and he acts like a p-rick sometimes and chases her.
Even with i had my Powder blue in there with my purple tang, Majestic Angel and Blue face there really was only chasing back and forth and nothing more.
With my clowns now i have a paired Wyoming whites and paired nearly nakeds and they chase each other as well but nothing more than that.
If his tank gets any more aggressive, we can always get rid of some, pass them on to me, or sell them.
It is also said everywhere... cant keep angels with corals and clams...
Powder Blue are reef safe... NOT
If anything my powder blue destroyed my 2 gonis, and picked at EVERYTHING else.... He had to go...
My angels really only pick at my red lobo, for some odd reason the leave the green one alone...