My personal theory, formed after reading a collection of opinions thru threads 12&13, several unusual discrepancies in the timeline & official releases, and statements given by family members to traditional media outlets:
I believe the intended target was Xana. (Secondary Q's: Has she always had the 2nd floor BR? What was father referring to when he stated she had "recently turned her life around"?). I believe there was a triggering event that occurred earlier in the night; the timeline given by LE still does not account for several hours. First they released X & E were at party from 8p to 130a. Then they changed it to 8p to 9p five days ago. Yesterday they ammend their timeline to say that X/E arrived back home at 130 but did not say they attended the party entire time. (Additionally, this would explain the specific request for tips about the frat party. There has been rampant, thus far not founded, rumors of an incident at that party. Frat also went dark online unlike the girls' sororities). Conflicting the released info is X'S father stating he talked to her around midnight. (Partying at a frat...take 5 min to call dad at midnight?). She told her dad that her and E were "staying at home to watch a movie"--if this is true I doubt police would leave the timeline as-is.
I initially believed the killer (singular) entered home via the 2nd floor sliding door. In this scenario going to the 3rd floor would be unnecessary and undermine my hypothesis. After the photos of roof, 3rd floor balcony, tree line, etc. I believe killer entered through 3rd floor sliding door-perhaps had waited on roof as one person theorized, but most likely utilizing the relative privacy of the wooded side of house and steep incline. I believe this entrance afforded killer most private entry, perhaps thinking he could sneak in, or that possibly the room would be unattended (Kaylee had been out of town)(Also goes back to my inquiry about previous room occupant). Killer enters and makes quick strike to K, possibly K & M both (I believe they were in same bed. But this info has not been released). Killer then moves on. Perhaps to M's room, perhaps surprised that the duo are each still awake (whether because of dog issue, drunk dialing, etc).
I believe that the red liquid photographed is that of blood (as ME or coroner had confirmed in a media interview). That is location of a 2nd floor bedroom according to Floorplan. I believe this scene was the most violent. (X w/ defensive wounds)(Visual blood loss through wall to outside). I think there is a possibility that either E or X had wounds/were staged leading LE to believe it was targeted. (An ex? A Greek member?)
I believe Killer exited via the far side of the 3rd balcony. I do believe that is blood (there is no other spots with "berries" leaving marks like that....and the marks are about the width apart as two hands lowering themselves down/hanging from the balcony to quietly as possible drop down).
Sorry. That was long. All MOO. I wanted to be clear and concise so to make clear.
I also do not believe Killer knew about or cared about the first floor & it's inhabitants. The 911 call and The Dog to me are interesting, but I believe they are intangibles not of direct importance to case. I believe the police somewhat "focusing" on K/M is a public misdirect, and that the specific request for info/tips regarding the frat party and subsequent events is very telling.
Edit: PHOTO BELOW for context of theory
