It seems to me, Ruth, that a great deal in your logical development turns on whether Anglian "Molly" dancing is a form of morris and was so named. I am not an expert on either. Many molly sides seem to have pretty well no moves that look like border moves, but some do have some moves that look like some border moves (but none that look like cotswold or longsword, and not much like any male or female northern clog that I have seen).

Sharp of course refused to accept molly as a form of morris or folk dance and he spoke of it as degenerate.

If then molly is separate in derivation from morris, the existence of the blackface molly tradition undermines the assumption that backface morris is tainted by minstrelsy, as would proof of a morris blackface tradition predating minstrelsy.