I suppose I'll make this a FAQ post? Ask me anything! Though I don't think there's much that's worth asking me.
EDIT: for any of you still hanging around here, note that 9th Ave has been providing fine translations at a regular pace, so hop over there for your textual No.6 needs.
Where can I find the end cards?
Ep 1 / Ep 2 / Ep 3 / Ep 4 / Ep 5 / Ep 6 / Ep 7 / Ep 8 / Ep 9 / Ep 10 / Ep 11
What's up with Nezumi's mice? Are they real or robots?
He has both real and robot mice. The named ones - Tsukiyo, Cravate, and Hamlet - are the live ones. The robot ones just pop up from time to time in moments of need, like the projector mouse. They never get named and Shion doesn't seem to notice them much, so I'm guessing Nezumi just keeps them in storage somewhere.
Who is Shion's dad/is this important at all?
It's never revealed and it's not important. Shion said that his father left his mother soon after he was born, so he has no memories of him at all. Apparently he was a borderline alcoholic and a womanizer, so yeah. They bring up the possibilities of Rikiga or Rou being his father, but they're quickly disproved.
Is it Shion or Sion?
Both are correct. Japan uses "si" in the rare cases where they romanize things, while the Hepburn system uses "shi". We English speakers need the "sh" to know how to pronounce it and the Japanese don't. It doesn't make sense for them to use "shi" when all the other spellings are sa/su/se/etc. Neither are wrong, it's just a question of which romanization system you prefer.
Is it Mouse or Rat?
Mouse. Volume 5 made this clear.
Are they bees or wasps?
They're bees. Volume 9 made this clear.