I agree, BA Tetras would be dinner one day.
I'd be careful mixing South and Central American Cichlids - although quite closely related they are quite distinct groups with different kinds of behaviour and water requirements. I'd probably be led by your tap water as to which route to take - if you have harder water go Centrals or softer go Souths. Centrals also take it a bit cooler than Souths and temperature is an often overlooked parameter that has a big impact on our fish.
In a 90 gallon tank I'd personally be looking at doing 2 Blue Acaras and a smaller Severum species like Rotkiel or a Liberifer and thats it (I'd also be crossing my fingers for all males or all females to avoid breeding). I had a Liberifer for 8 years and she was a great fish strongly recommended! The great thing about American Cichlids is you need to mix them with a community of fish to replicate their habitat. And there are so many interesting choices, Wood Catfish, Armoured Cats, Headstanders, Hatchet Fish, Pencil Fish, Plecs, Whiptails - the variety of Tetras and Characins around now is incredible. I saw a photo of a group of Annostomus Ternetzi with a group of Synaptolaemus Latofasciatus (google them) and it looked amazing!
I always cringe when I see people with a tank of just American Cichlids, its not natural for them at all. It's taken me about 20 years to realise but if you want a tank full of cichlids, loads of colours and shapes and temperaments, go African Rift Lakes - Mbuna, Peacocks, Tropheus, Tanganyikan. They can seem a bit daunting (they really aren't) but so many people that squeeze in Americans really want a Rift Lake tank and they just don't know it yet...
Wills