I might leave out James, but then he is trying to sing heavy metal, and that makes him a poser to some people, so he doesn't even much of a chance, and Lauren? Well, Lauren dresses like a televangelist's wife and so does her mother to hear it said on the FORT, so Lauren doesn't get a chance to have any irksome gestures either ...
For the rest....I think that those nerve-racking gestures can be worked on with good coaching. Somebody can coach Jacob how not to flounce around, glance out of the corner of his eyes, and whatever else he does that is distracting.
A professional can show Haley that moving her arm up and down like she is cranking up a machine while she is singing does not aid her performance.
Scotty most likely does not realize that he looks dorky holding the mic and singing out of the corner of his mouth. However, when he is shown what he looks like by someone in the field that he looks up to, he will respond!
Likewise, Casey, I am quite sure is totally unaware that while he was performing last night, at one point he leered like the big, bad wolf in Little Red Riding Hood.
In the same manner good coaching will help James and Lauren as well in whatever areas of weakness the two of them have.
Coaching will help eradicate those annoyances; on the other hand, no amount of coaching will ever help if there is no ability. That is not the problem!
Scotty in my opinion is destined for success. Somebody will help him get rid of the annoying habits he is developing. That will come with time.