I honestly think it is a whole lot of guessing, The only thing I know for sure is that these people should have been identified and asked if they saw or heard anything unusual that night. Do they remember what made them look backwards.
Beyond that we are just playing a game of "I wonder".
I agree. My best made up guess would be noise but not the 25 minute death scream. Noises that were alarming but not extremely loud. An occasional shout, whimpering, sobbing, maybe pleading? But mostly soft enough to not alarm the people into calling the authorities. Just a domestic dispute, nothing to see here, move along. That kind of thing.
The window was broken at this point making these types of noises audible across the street.
Another question though, didn't Meredith get home at 9:00? Rudy was supposedly in the house before she got there. This sequence of film ends 1 hour and 5 minutes after that! It gets weirder doesn't it?