Since the other Malawi you listed are all mbuna, I'd skip the Moorei as they're Haps and 100g is too small to mix the two. I definitely wouldn't put Demasoni and Cobalt Blues together in only 100g. Demasoni can be incredibly vicious toward con-specifics, despite their small size. I'd even hesitate to mix them with Acei. They do NOT like any other remotely blue fish. Since you already have one Demasoni, you'll either have to take it back and switch to Cobalt Blues or Acei, or stick with just Demasoni. The Yellow Labs should be okay so long as you get a big enough group of them - they'll be safer in numbers. Some say that Bumblebees are aggressive toward all con-specifics, but I've got Yellow Labs in with mine and they couldn't care less. I think they only really have problems with Auratus.
I'd do Demasoni OR Cobalt Blues (NOT both), Yellow Labs, Bumblebees, Red Zebra, and if you really want another type, maybe Snow White Socolofi? You could also get some Synos. Just make sure you keep your stocking levels up, especially if you decide to stick with the Demasoni. You really need decent numbers to dilute the aggression. Also watch your filtration (mbuna need a lot) and keep up on the water changes.
As for the 55g, I personally thing it's far too small for 3 RTBS. I can't comment on the others because I know almost nothing about SA cichlids. The only one I've ever kept was a Red Devil I had years ago.
The Moorei he is talking about are from Lake Tanganyika. Not Dolphins.
I would get rid of the Americans and the Demasoni. Stock the tank with a good number of Mbuna (what filtration permits). Demasoni are best kept in groups of 15 or more and are extremely aggressive.