Ai made the most since to me, Carol gives off the same vibe as Ibis at times. Chief is a bit wackier then you would expect your Nineball derivative to be, rather like his cheer though lol. Then again I hear Wally Wingert and all I can think is Invader Zim. Moving on from that though, Zodiacs feel like test subjects for human plus modification, kinda wish they had taken that story a bit further and maybe mixed it into a few more story missions. Heart emblem is Rosary's emblem, from her backstory with MOH which the order missions hit on.