Reevol is the only one besides Yeyeen who has a white top and so I'm guessing he's got a swoosh too, because in one scene he's there at the same time as the other swoosh:
Yeyeen would normally be easy to figure out. She's the only girl besides Aroree. The only problem I came up with was that there ARE no other female Eight in the third book; only in the fifth and sixth (and really just the sixth). So I managed to have a leftover Eight with a white top who wasn't Reevol, who was male, but feminine looking. I guess he/she got a sex-change from Winnie after Voll died. (My guess is that Wendy wanted another female Eight at the last minute.