Well from my experence with them I found they do better in groups wit a male to female ratio of 1/3 or more. I'm not gonna say it will not work but the blue dolphin I believe is a more docile and slow growing cichlid and may get harrased. Ob peacocks are kind of a wild card since they are hybrids some can be very agressive while some more passive. And you have a mix of vegitarian and carnivor so a food like new life spectrum cichlid formula would take care of feeding.
Those are just my opinions. I kept a large random mix of cichlids in my 125 and it was trial and error until I got a good mix. Just watch out for agression when they mature. Hope that helps a little and good luck.
