It either means more like the hormone your own body makes, or it means not made in a laboratory. It is not natural to have progesterone postmenopausally for example. It is not natural to have estriol or estradiol postmenopausally. So I really don't know what natural means. The risks are the same.
Fibrocystic disease is a garbage term for lumpy painful breasts.
It does not increase the risk of cancer in most cases. There is one condition which is only diagnosed microscopically that may increase risk. That means you have to be on it when you have your heart attack. Some people are starting to suggest that we take it briefly if we need it around menopause and then taper off. It depends on alot of factors.