Small cichlids, in small groups, in small tanks will be shy. I always get 6 juveniles of any fish to grow them out because they seem to be more comfortable in groups. This seems especially true for young geos. The lip-locking and fighting you see is the fish trying to work out their pecking order and establish who is the dominant fish in the tank. Again, this is more evenly distributed over a larger group so that too much stress isn't placed on one or two fish.
Keep in mind that dithers in the tank do help them feel comfortable. Without them, it sometimes takes longer for them to adjust.
Things like shadows and vibrations will also scare fish. Look how your tank is positioned and see if there are shadows being cast by a window or an overhead light when you're approaching the tank. Putting them higher up works too but I can see where that's a problem if you use a standard aquarium stand/cabinet.
Start out feeding them something enticing like frozen bloodworms. Most fish can't resist those. Turn the filters off, defrost a bit in tank water, and pour it right over where they are. It will usually sink to the bottom and they will find it and eat it. Then you can try small sinking pellets -- I like the 0.5mm New Life Spectrum Grow. I feed this to all my cichlid fry, including Geos. At their small size it will take them a while to chew it and soften it before it can be swallowed, so you may see them spitting it out a lot, but they are sand sifters by nature and they will find it later and eat it. I'd avoid any flakes or foods that float around and get sucked up in the filters. Geos instinctively sift for their food and I've found that they feed best on sinking foods like micropellets, bloodworms, etc.
As with any new fish, it takes time to adjust to your tank, your schedule, your room traffic, and so on. Once they start associating you with their favorite foods they will liven up and hide less.
