I wouldn't say you couldn't make this list of fish work. With Cichlids it's hit or miss on temperament sometimes. Be prepared to possibly remove and separate highly aggressive fish.
If you go with this list add all of the Cichlids last and at the same time as juvies. Stick to your caves and plants to block line of sight and for territories. If you are worried about plants being uprooted put a few moderate sized stones surrounding the base of the plants.
Your tank wouldn't be overstocked IMO
. However, I would go with Bolivian Rams over German Blue Rams to minimize possible aggression between ram and apisto.
10-12 diamond tetras is a good number. Anymore fish besides what you listed would be getting into overstocking IMO
I'd also get a second marineland C360. You'll want between 10-15x tank turnover per hour. 50% water changes every week.
Is your tank cycled and ready to go?