Every critter can have a unique personality. I have raised Turkeys, Muscovy Ducks, Khaki Campbell Ducks, Guineas, Embden Geese and several breeds of chickens. I use several large chicken tractors and they all free ranged together and each tractor had a mix of breeds. For the most part it worked, I did however have some problems.
In one cage I had mix chickens and Khaki Cambell ducks. A Chicken went broody and hatched out some chicks, everyone in that tractor got along, but during free range time I had a turkey go into that cage and kill all the chicks. I didn't expect that, the turkeys grew up around chickens and they never bothered the chickens. The turkeys were midget whites.
Guineas were also a problem. For several years I raised guineas and chickens together, then for whatever reason two years ago the guineas decided they hated roosters and would harass and fight any rooster. They had to be seperated. They only went after the roosters, and while they were the top dogs in their cage they didn't really bother the hens. Since that time I have not mixed guineas and chickens.
Another problem I had was a rooster fighting with the Khaki Campbell drake.
If you have separate coops for each and the area they are ranging in is large enough and they are raised together I think it would work. I did it for years and the problems I had I have mentioned. Everyone's experience can be different due to the critters personality, the environment and other factors.
I never had a problem with Muscoveys and chickens running together. Turkeys mixed with chickens are not a good idea due to blackhead. Chickens can be a vector for blackhead.
I have no first hand experience with emus or pheasants.
