Most apistos have the same requirements, and most stay under 4", all of the undescribed species you mentioned would be ok at pH 5.8-7 with very soft water required for breeding. They usually take frozen bloodworm, but with a bit of work will accept Tetra Prima, which is a high protein diet. Bloodworm doesnt have enough protein to give the apistos enough energy, so it cannot be their only diet. Frozen brine shrimp is also taken, but again will not mak a balanced diet.
All are territorial, and its best to keep one male to three females, with only one male per 2ft of tank. They are mid-bootom dwellers and like a sandy substrate.
The single described species you mention, veijita has a rep for being a little terror, and males will fight no matter what size the tank is. They will attempt to harass any other tank occupants too. The inca or papagei get my vote for looks, the malbruter is pretty plain, except for shimmery scales and it also has an intersting mouthbrooding method of caring for fry.
In a 3ft tank, you could put three species of one male and two females of each type, except the veijita, which is best kept alone in a 2ft with three females or more, so one does not get too much unwanted attention.
The fry of the trifasciata and mamore are both slow growers, the rest are quite hard to breed but thrive on newly hatched brine shrimp, then bloodworm and flakes.
Ken