For example, we know that at least 12% of English is from Greek,( 35% according to some linguists), and we dont have any evidence for most of that, but does that mean it is not a fact?
This makes absolutely no sense to me. Whether or not the above %'s are true, if we have no evidence for it, it is NOT a "fact", it's merely a speculation.
The pronunciations of
Harry and
Henry were IDENTICAL in medieval England; that's the point that experts on the history of names are making when they show the connection between the two. The modern English pronunciation of "
Henry" is newer than the pronunciation as "
Harry", based on
Norman French. It is of no consequence how old "Harrys" is in Greek in deciding whether or not the modern English name
Harry is connected with it.