if we're talking about creatures not necessarily human-like:
jiwoong: pegasus
hao: angel/siren
hanbin: witch
matthew: baby dragon, specifically
taerae: siren
ricky: vampire
gyuvin: not sure. satyr? cerberus? baby vampire?
gunwook: could be a cerberus with gyuvin (and ricky) lol. centaur?
yujin: witch