I'm not an expert, so feel free to correct me anyone, but as my knowledge goes, Epicattleyas are a hybrid resulting in crossing a Cattleya with and epidendrum. They are in the same family, which makes them compatible. Hope that helps!
Still new at this, should have known, actually stumbled onto the answer in the awesome compilation of genera/species of the Santa Barbara Orchid Estate.
So despite the order of names in the genus, I take it that the "real" name is Cattleya x Epidendrum, in that order.
Epicattleya = either Cattleya x Epidendrum OR Epidendrum x Cattleya. In fact, many of what you find commonly called Epicattleya is likely to be a Catlyclia, Cattleya x Encyclia. This is because many were created before the genus Encyclia was split off from Epidendrum a number of years ago. Even more confusing, most who have been growing orchids more than 15-20 years will use the shorthand "Epicatt" to describe any hybrid of a Cattleya-type hybrid (or Cattleya species) and an Encyclia/Epidendrum.