The information that I have read, from both books and internet sources, describe them as I previously stated. Thus, my previous statement is not an assumption if all information regarding the being has been consistent in definition/description. Below, I have provided sources regarding this particular topic.
Also, the Greek word daimon referred to any being, spirit, deity, etc that was either "good" or "evil." Incubus, at least in my research, has always fallen into the latter category. I've not come across any information placing the entity in a positive light.
The Witch Book: The Encyclopedia of Witchcraft, Wicca, and Neo-Paganism. - Written by Raymond Buckland.