Coach Sasabe will turn out to be Easter Dave.
How else would they translate Sasabe finding out about Miho's former, erm, line of work?- Being in weird porn.
Rei is Easter Dave in disguise.
He's said some fairly suspicious things (such as being weirdly interested in Nagisa's claim that no one would care if Haru and Makoto went missing) and he's completely unimpressed by Nagisa's criminal reputation. Could it be that he's done worse? Nitori is Easter Dave.
Rei is just a Red Herring. Nitori is actually a criminal mastermind hiding in plain sight - who would ever suspect him? Sousuke is one of the several Easter Daves.
It's already been shown in Fairy Tail Abridged that one Easter Dave exists, but the 50% Off! Anime Expo panel also included a desire to have Lelouch Lamperouge as Easter Dave. Seeing as there are two, who's not to say that Rin's brooding, decidedly shady friend isn't an Easter Dave too? Nagisa will mention his cousin offhandedly.
Octopimp & Sparky The Android will collab with TheOutbackAl
for a Puella Magi Madoka Magica cameo featuring Nagisa and his potentially half-vampire cousin Madoka and the Pokemon following her around.