very understandable that she is.
agree - yes we heard from ex occupants of first floor - irrc, only heard noise from 2nd floor if TV was very loud
I still think it's possible that the 2 survivors did hear something but as you all have said previously - if that noise was ambiguous and this house had long been party-central , survivors could have dismissed that noise.
let's put it this way;
If you as a survivor, heard a noise but didn't react because it sounded like a nothing-burger and the police expressly told you not to speak to anybody now & not to tell anybody because it might scupper a prosecution, what would you do? Would you phone for example, Alivea G or Hunter C/ any of the family & go tell them out of empathy? Tough call imo