Click to see Spoiler:
As I've mentioned in an earlier post, I figured Dana was killed because I saw a woman fitting her/Adrienne's hairstyle and physique be drugged by the killer. Of course Adrienne is dead so it'd have to be Dana.

And note - I'm basing this on TEASERS only and what I saw at the crime scene. This will probably have to be adjusted for the clues.

Based on the teasers I'm thinking this is going to be tantamount to Vincent Price's bad guy in "The Wax Museum."

But difference here is that both girls were bled out and injected with wax or some sort of stiffener as well as doused with formaldehyde to protect them. Or the reverse - preserved then dipped in a more satin wax.

So - this is what I'm thinking - because there were two deaths, you'd have to make sure that both were unable to fight. The killer drugs Adrienne and takes her to the Morgue, then gets Sasha (or the reverse). They are bled out, injected with whatever they need to stand up, dressed up, made up and then positioned at the piano.

I put that they were drugged then bled out because I didn't see any wound marks on them visably, and no bleeding. Sasha looked a little paler.