Good questions!  When it comes to "facts" about the characters, I like to leave as much as possible open to interpretation for the viewer.  I have my own sort of continuity in my head for them, and then everyone else has their own (yours is a lot of fun, by the way, and I like its positive attitude).  Kelli, in my mind, is one half Hispanic.  The other half is unknown.  Apparently whoever her mother had some strong genes for green eyes, as I realize that's kind of an implausible combination.  Tammy, meanwhile, is a sort of "guest Dame," who was added much later, and wasn't originally intended to be part of the group.  Of course, there's no reason for her not to be, other than I don't know much about her.  At one time, I'd considered making her part of some kind of "urban fantasy" or "supernatural" setting, but canned that idea quickly.  The real reason she's there is just to appeal to a particular fetish, for those guys who like to see an absurdly small frame carrying an absurdly large rack.  She's actually going to be appearing much more often for a while, as she's taking Dasha's spot in rotation for now.  Meanwhile Maisey on the other hand (my favorite), was intended to be a full-figured girl all over, so she's intended to appeal to a slightly different group.