The thing that confuses me is, as you say, this is plagiarism as Hard Work. No simple cut-and-paste with a find-and-replace of the names here. The only reason I give her "pastiche" defense any credit is because I can think of no other reason for her to go through all the work to incorporate these stolen passages. But, if that had been her intention, I would have expected her to say something at the beginning of each post that the fic following was a "pastiche" involving borrowed concepts or quotations from other works, and then at the end list specifically what was not her work, and where it came from. Sure, it could be a fun little game, like going through The Eleventh Hour and trying to figure out from the clues in the drawings who stole the food. But it only works if everyone knows it's a game, and not merely someone's fanfic.

I have a hard time picturing doing something like this once, never mind as much as this woman has. If I had a character in an HP fic of mine say "a vague disclaimer is nobody's friend," intending it to be a nudge-nudge-wink-wink to any readers who were fellow BtVS fans, I would say something at the end of the fic to be sure that any non-BtVS fans knew that wasn't my line.

I can only hope that the Wikipedia page you linked to about this situation is incorrect. The fact that she might have gone to my college (Vassar) makes me feel the same way you feel about her claiming to have been a reporter in the past.