Ooh!
Now, THAT is some plot!
I've read my share of HP fanfics, but what you had had done to the girls was truly horrible! And (afaik...) never done before! But at the same time, I've never seen a more credible plot to have both Bellatrix and Narcissa with Harry.
I have the feeling that there will be some big problems ahead (be it because of the Order or the Death-Eaters) and that the meeting with the Tonks will only be mild in comparison...
The fact that Hermione is jealous of the Black sisters will certainly add some fun to it :-D (Luna strikes me as a sharing one...)
Please, update soon!!!
(I just realized something: It may have been kind of polyjuiced, but Draco's mother is an Inferi... And Lucius had sex with it... I wonder of their reactions when they will learn about this fact... I also wonder what a marriage to an Inferi mean, legally... Oh! And it may explain Draco...)