Yup, that's Jewel. Sean Stockman looks much older this time round.
I've been digging more info about the groups and it seems nearly half of them are brand new, formed specifically for The Sing-Off (Element, Ten, Calle Sol, Filharmonics).
Out of the groups I know, I am most familiar with Voice Play mostly because I watch quite a lot of acapella videos on youtube. And honestly only 3 groups stand out and come highly recommended by me. Namely, Pentatonix (Season 3 winners), the current batch of BYU Noteworthy Ladies (Season 1 contestants) and Voice Play. So I will be very happy to see Voice Play on the Sing-Off stage, they certainly have the talent (link
). I had hoped that Noteworthy will once again be in The Sing-Off (just listen to this
!), but maybe there's some restrictions on having a past group re-enter the competition even if the members are totally different.