Ohhhh. This silhouette guessing game looks like fun. I'll have to check out the various seiyuu threads on 2ch later to see if they've got the whole list down already (wouldn't surprise me!), but for now... I'd be tempted to call Atsushi Abe, Kimura Ryouhei and Hayami Saori in there (as 2nd ~ 4th). #2 should be possible to find since there aren't that many short seiyuu around, but the hairstyle doesn't seem to fit Abe that well, and I don't think it works for Ishida Akira either... well, there are a few remaining such as Hoshi Souichirou, Irino Miyu and Yoshino Hiroyuki, but I can't picture them either.
At the very least, I don't think Kugimiya's in there. Both female silhouettes are taller than the shortest male, and he shouldn't be anywhere below 160 cm. That also narrows down the choices for the females - most likely no Sawashiro Miyuki for Mor, which would've been pretty cool. Unless they're tricking us with heels.
EDIT: Now browsing 2ch for possibly interesting tidbits - it seems very unlikely that Miyano's in there, as he's already got a fanclub event booked on 09/30. As much as I like him, color me pleased because unlike most, I just don't think he's cut out for Alibaba. As for the rest, they're just throwing very wild guesses and haven't made any certain guess. They've made me consider Toyonaga Toshiyuki for the smallest guy, though.