I have 3 American...2 blood parrots n a green sevrum
I figured that you may be fairly new to raising Cichlids since you didn't know about Kenyi's changing color.
I hate being the one to tell you this but some of your fish shouldn't be kept together. Some fish can adapt to almost anything, but that doesn't mean that they are thriving.
The biggest difference is with your Favorite Kenny (the Kenyi) and your Green Severum.
Your Kenyi will grow up to 6" & needs a minimum 50g tank with a pH of 7.8-8.6 and KH of 10-15
The Green Severum will grow up to 8" and will fit in the 50g but the pH needs to be 6.0-6.5 with the KH being 4-5.
Those are some pretty big differences for them to try and adapt to
As far as your Americans, chances are that they have water needs closer to your Green Severum, than they are to your Kenyi.
It's never a very good idea to mix Africans with Any of the South American, North American, or Central American Cichlids. In fact you shouldn't really mix African Cichlids for different lakes. Your Kenyi is from Lake Malawi, which has to many different types of Cichlids to count.
Your Blood Parrot is a whole different story. Many people in this hobby are trying to have them out lawed, due to their deformities caused by their selective breeding. I always liked them too, until I found out about how they were bred.
I really hate being so negative about other peoples choices in fish but we all want whats best for the pets we love so much.
Blood parrot cichlid - Wikipedia, the free encyclopedia