I have had blue cherries, as well as some that were almost black. They did not have that tiger like stripe pattern I see in the pic. Unless that is a photographic artifact from the angle of the shot. That is what they looked like body wise.
As to the OEBT without the OE genetics question. The OE trait is recessive, thus if they are bred with wild type they will lose the OE. Crossing them back, would bring them back in a about 1/4 of the offspring.