For the harem, I'd actually like to see you do something different as far as girls go. I'd have liked to see you use non cliche girls. By cliche, I mean Hermione, Luna, Ginny, Fleur, Tonks, Cho, Susan, Hannah, Daphne, Tracey, and Pansy/Bellatrix/Narcissa/Marietta (because he wants someone to abuse), but you've already taken Tonks so I guess that's not gonna happen. I wouldn't mind seeing some one from completely left field, like Eloise Midgen, Heidi MacAvoy, Millicent Bulstrode (she doesn't always have to be made a hidieous monstrosity that only Crabbe or Goyle could want), Lisa Turpin, etc. Also wouldn't be opposed to a professor, maybe Sinistra, Vector, or Burbage (Muggle Studies), or maybe the hot new Defense Professor. Also while I know they are cliche, you still can't go wrong with Twins if you catch my drift.
For the slave thing, I honestly don't care.
Also, just curious, is this possibly a pornographic readaptation of ideas inspired by the manga Death Note.