Seems unlikely that Biden would be going to political events in Delaware while he was VP. Can't say for certain, obviously. And Murry's insistence that she was 14 at the time makes it unlikely that she got the year wrong anyway.
So either she mistook the identity (though O'Donnell claiming to be there makes that less likely), or she lied (although it seems unlikely that O'Donnell would go along with that too).
Is it too contrived to speculate mistaken identity AND O'Donnell's claim to have witnessed it directly is a false memory because she's heard the story so many times intrafamily over the last 12 years?
No, O'Donnell is a tea party lunatic, she is either lying or simply backing up her niece and assuming she's telling the truth.
Her niece is lying. She saw that the Tara Reade lie worked and wanted to try it on for herself.