I'm not sure a 120g tank would be big enough to house 4 adult frontosa and all the other fishes. They would be fine until about half grown, then they would need a bit more space. You really want a 6x2x2ft tank for adult frontys.
Fronty & blue dolphins will be fine together. Aulonocaras and red empress should be fine too. Not sure what a giraffe cichlid is. Calvus would be fine until the frontys are big then might get chomped. Rusty should be ok. I don't like Malawi eye biters (D. compressiceps) because they do exactly that. Bite out eyes. Not always but sometimes, so I prefer not to keep them with anything expensive, ie: frontys and calvus.
If you put a group of those together as young fish they should be fine but you will have to watch the water quality. As the fish mature they will need a bit more room and or more water changes to compensate for the extra waste produced.
You could get a double tier stand and have two tanks 100-120g on it. The top tank to house the fish and the bottom tank can act as a sump to hold extra water. This would increase the total volume and allow you to keep the fish in a slightly smaller space with less water quality problems. You could then keep a group of calvus in the bottom tank without having to worry about them being eaten.