I suspect that Damien has a lot of muscle in addition to body fat. If the team was doing primarily strength training (like pushing Jessie on that heavy heavy push thing), he may have been doing less fat shedding and more toning of his already existing muscles. His arms look like pure muscle, rather than fat. He also retired only 3 years ago, so again I suspect he's retained some muscle. I believe (but could be wrong), this could account for his low number.
Jen looks like the love child of Gillian and Emily Thorne from Revenge. Her love-fear thing is already annoying. I wish for once there would be a trainer who comes from a behaviorist point of view and talks about classical and operant conditioning, etc. but they don't teach that in armchair-psychology school.