About Scratch and her sexual agenda ... Your argument is: Scratch could be this and this, because on the complete show we have no indication for what she likes - hetero-, homo-, bi-, objecto- or a-sexual.
Dude: Then most characters in this show could be anything. I wonder what makes Scratch so special to think about her sexual agenda. Because she is supposed to be the main villain on the side of the humans? Or that she has some of the most awesome quotes and scenes on the show? That she has such a brutal background-story, which would explain almost anything that is not aiming at hetero?

Really ... No clue what to think about it. In my humble opinion: If Scratch ever finds the right person to fall in love with, she may even share some acts of love with that person. Actually I don'T even care what type of sexuality this would involve. Does it matter anyway? No.