I'm wondering if there is more dirty laundry than we've seen so far. Something worse, maybe.
However, if you want to convict your daughter's murderer, none of it should matter at this point.
Why not just say, "Yeah, we and our friends are sleazeballs, druggies, and we do a lot of things that may disgust other people. We'll truthfully tell you every detail of that night and any prior occasions. We want to be straightforward in order to assure you that neither we nor our friends had anything to do with Danielle's murder. We want to cooperate 100%."
Seriously !!!! If you believe that Westerfield actually did this, but your lying and evasiveness may create reasonable doubt, wouldn't you lay it all out there?