They would do fine in that mix for the most part. I've never tried mixing CKs, but I've seen people with a pair or so in their tanks before. CKs can be aggressive, but all the ones I've ever had have been pretty mellow.
My 22" CK is a brutal, destructive monster sometimes....problem is you can never tell which fish he's gonna murderize...For instance...shredded a 24" Afr lungfish, but not 14" poly, shredded 18" pacu but not 12" Leptobarbus, ignores a 10" Royal CK which I expected him to destroy.
Mine is 15+ inches and he is fine with my 4 severums.. as you can see but it all depends of all the sizes of your fish..arow size ..oscar size and ck size..because ck could be eaten by them as well.
Thank you ..i love my boy.. 000000080000 haha Do Your fish eat live food..big thing i think..my CK was only 4 inches when i got him last year..he ate live food..i switched him over and had him in his own tank until he reached 12 inches.. he was in shock when he met his first other tank mate.. so he has no idea of aggression ..except get out of my way for those pellets..so i really don't know how one would fit in..but i know when they are young they are timid and fragile ..