I have a situation where those of you with the custom facts would have migraines.
I have a whole family that is tied together by a family document that was was written about 1826, and support by the minutes of 20 years of reunions between the grandchildren and great grandchildren of the original family. Were grandchildren related? Probably, as if not, they would not attend this reunion for 20 years. There is no one set of minutes, or document that proves the relationship, it is the body of documents.
I think each "fact" has to be handled separately and the reason that "fact" is a fact should carry some sort of explanation. To just say because the birth certificates says John Doe is the son of Mother Jones and Father Doe, does not make it a fact for YOUR family as there could be another Doe family with the same family names.
Documents which we consider facts are only facts in the context of all of the other documents that you have in support of the family conclusion. To make a series of labels for the "fact" is in some ways a waste of time, you need many notes to explain the why of accepting documents as facts, and then the note must be a logical presentation of the reasoning for acceptance.
In my example the Reunion Notes are a fact only because they are supported by many census reports for many families, many birth certificates and many birth death certificates. The various families relationships are only valid because of the Reunion Records.