I can answer a few of these.
It is supposed to be Cheshire, like a Cheshire cat.
I believe Jigoku no Kami is male, but I could be wrong.
As for Bael, this kind of sake.
1 sake, interest
a reason for wanting something done; "for your sake"; "died for the sake of his country"; "in the interest of safety"; "in the common interest"
I'm pretty sure Hazael's stats are pretty intentional, since her guardian is an Alius.
I find the whole "measurements are all the same" thing kind odd, but the ratio is more varied then some people are willing to admit: 110/78-62/50-95/81 is the spread, and considering we are talking anime/supermodel proportions for all characters here, that is a pretty significant spread.
The Wake is a plane of existence between Gaia and the Spiritual Realm. A great number of Supernatural Beings (summons in particular) travel through/live there. Emotions of beings in Gaia can heavily influence The Wake, changing the forms of certain areas and influencing the inhabitants of the Wake. From my understanding, its appearance is that of a warped version of Gaia that is constantly changing, and several areas in the Wake are lorded over by incredibly powerful Supernatural Beings.