At those small sizes, the red heads, the small altifrons and the jurupari should be kept in groups of 4+ of their own species. The issue I believe you're encountering here is competition. You have all four species that are in competition for the same resources and space, so they are attempting to chase the others out. Unfortunately, there is no where for them to go.
Do you have plans to upgrade in the future? If not, I would think your tank is going to be too small for all those fish to live together peacefully.
As a general rule of thumb, earth eaters need groups of 4+ of their own species to feel comfortable and thrive when they are young. Once they hit about 1/2 to 2/3 their ultimate size, you can drop them down to singles or pairs. The red heads are generally a very passive fish (even for a geo) and it will likely end up being bullied by all the other species you have there at adult sizes (take this with a grain of salt since each cichlid has its own personality). The red heads max out at 6-8" depending on gender while the others tend to hit 10-14". Earth eaters can be really hard on one another if kept in too small a group at young sizes. They also can be rough with similar looking species or species that use the same portion of the tank if they are feeling crowded (since you have a 100 gallon, I will assume it is either 4-5' long, so they might be feeling a little cramped).
Having said all this, I would recommend narrowing down your stock. Either drop the smaller fish to keep 2-3 of the larger guys or drop the larger fish and boost the numbers of the smaller guys.
S. leucosticta are hard to come by and since it sounds as if it's not being picked on or doing an of the aggressive behavior, I would keep it along with the large altifrons and maybe the jurupari.
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