That is NOT a wig that Lisa is wearing. You don't show a part with scalp and a different color hair at the roots than on the "ends" when you're wearing a wig. Plus the hair has lengthened since the start of the show. Why she would choose to go to flat, stark, black hair I don't know but the true, possibly reddish-brown her is growing out.
With Kelsey, she "abdicated her throne" as far as what she was there to do (cook), and she knew it, and was worried about it. What she got from Rachel ("What are you going to do while I'm doing your job?" or something to that effect) was well deserved. She could benefit from more life experience, also. She has potential, but it needs to be developed.
People who sweat heavily should ALL be using head bands. Yuck, Aaron! Really enjoyed his segment, other than when he turned his back. He was the only person who stressed always wash your hands before you start cooking.