Isabella Minor Todd can be traced all the way back to Ancient Roman emperors. If this Madison woman existed and was a daughter of Mrs. Todd and John Madison, then yes, in answer to your question she can be.
My question was not about that however. I was asking for information on whether or not it can be proven a Catherine Madison existed.
I do doubt the user created sites aren't reliable, that is why I am here asking questions for more reliable information that what I have. The Madison line CAN prove it's ancestry, but I can't find any proof of who Richard was married to.