My theory on the Rep confidence is that there is hard proof the future judge wasn’t there at all and even maybe out of town. Of course that would require that the accuser actually have a timeframe and/or an actual location for this imaginary event. ;-)
I think the doppelgänger theory is ridiculous, but there is a reason why it is being floated.
Perhaps it gives Blasey Ford a way out of her predicament. Or perhaps it’s a way of telegraphing that others know that she has the same allegation previously, but involving other people.