Yeah Matt was very full of flu/cold for the last few weeks but never played on it as an excuse.
Rebecca... on the show she had this awful vibrato/warble that went from an in key note to an off key note, it was very odd and harsh on the ear, then she had this other weaker warble she would use that sounded like she was gargling mouth wash. Not to mention the fact like you say seemed glued to the spot the entired series and made all songs sound the same.
I still dont understand who voted for her, did those that did just buy into the propaganda that she would be a great recording artist from the judges? or did they just not like Matt? or worse still did they tear up because she kept saying she needed to win to give a better life to her poor sacked clothed, eating only stale bread kids.

Anywho I would question one thing about her and that is did she have the wrong vocal coach on the show, I mean she got more and more faked up Motown the more she stayed in the show yet pre the show this is her work
http://www.youtube.com/watch?v=GfeEMI96D-A&feature=player_embedded not bad IMO