One thing you may want to consider....
Many Geophagine are rheophillic (or at least semi-rheophillic, meaning they appreciate fairly strong current, slightly cooler temps and consequently, more and highly oxygenated waters than others....
Severums, and angels, are placid water species, preferring less current, and slightly warmer temps.
Being a biotope aquarist, I would probably not combine those cichlids unless the tank was large enough to be able to sustain both habitats at the same time,
an example might be a tank with a large and open sandy area with a power head, or wave maker providing linear flow across it , aimed strategically across the length os the tank for Geophagus.
One other Geo quirk, often times without that strong current to work against, and if temps are slightly elevated, as Geos age and mature, they become quarrelsome with each other (and may even take out that excess unused energy, on other species).
And different more oxbow habitat, a more logged or rocky strewn area with softer current for the severums and angelfish.
But as a personal quirk, if it were me, 'Id set up 2 separate tanks, instead of one, one in the 6 ft range range for the Geo, and another (maybe a 90 gal) tall tank for the angels and Sevs.
