We are a bit contradictory. When you get two source3s giving you info that contradicts, unless one seems more credible, ignore us. Go to a site like Seriously Fish and research the fish yourself. Either of the people trying to help could be kids who know less than you do, online. We're faceless people here.
Checkerboards are in zero danger, and are hard to find because Brazil is controlling all fish exports now. They come in, but prices are higher. They are not overfished. They've traditionally been inexpensive, and with costs rising, aquarists expect them to remain cheap. There's little incentive to import them from Venezuela or Colombia because of that.
Rams can be very inbred. But you can't pair them when you buy them, and in a decent sized tank groups will get along fine. They are not aggressive fish. Wild imports are rare but when I have kept them, they are feisty. Domestic rams are usually very different - much calmer. You will rarely see wilds. I think I've seen wilds 3 times in 50 plus years with tanks. So if you like them and can find healthy ones, they'd work.
So would an easier fish, the "Bolivian ram", M. altispinosus. They are a bit bigger and less flashy, but they are nice and hardier fish.
Kribs are soft water fish from Nigeria. That's where a poster saying they are east African confused the issue a lot. Eastern Rift lake fish come from quite hard water, and east Africa is known for hardwater species. The rainforests of western and central Africa are similar to Amazonia when it comes to water. The only real issue is that African rainforest fish are generally a little tougher than Amazonian ones, if there's conflict.
If you take a jump to a soon to be huge Oscar, expect to double the size of your tank. They are large, messy fish. Acaras are also larger than dwarfs and territorial. But they aren't the size of Oscars - not even close. You were originally attracted to smaller species.
Decide which species you like the most of the ones you were attracted to. I won't tell you what to get - but I can help you with choices to build around the Cichlid you really want.