Monet had the 'least obvious' edit, IMO. She's my first candidate until I can investigate who was where in the living room. If it was her, she (or the producers) might have figured that certain of the others would have trouble with the weenie challenge and that she didn’t need to do anything to sabotage her team.

Also I think that the door locking saboteur could not have been sitting on a couch with anyone else, his/her movement during the blackout wouldn't have gone unnoticed. But who's to say it did go unnoticed. First impressions of these people are that none of them are sly enough to keep that to themselves right now (the IQ guy notwithstanding), but it is slightly possible, I guess.

It’s obvious with that door locking trick that the saboteur has at least some of the hijinks planned for him/her by the producers, and that he’s not just winging it on his own. This means that the sabotage will be not be inept.

There’s also the possibility that there may be more than one saboteurs.