Im going to guess based on your set up there that you have acidic water and low hardness. Checkerboards are harmless and will be FINE with your rams. My only concerns are about water quality and environment. Checkerboards HATE water changes, meaning you will have to carefully get ALLLL the nitrogen, chlorine, ammonia, etc out of the water AND adjust its chemical properties befooore adding to the tank, Nitrates over 10PPM can murder them. They are super fragile.
I think you might wish to consider Sajicas, or the Bolivian Ram. Perhaps some small eartheaters? Blue Acara?
Im not sure you have the capability or environment to house the chekerboards. Tank mate wise you are fine.