Been traveling (oddly southern MN and NE Iowa) and not able to follow, so sorry if this was discussed. I'd thought about putting item #1 into my first post on this case but decided not to. Plus a random thought or two.
1) IIRC, the 12:31am time came from the neighbors. They said their clock was 7 minutes fast and deduced the time as 12:31. (Does anyone else recall this??) What if they were wrong or had the offset backwards? 12:38 plus 7 minutes is 12:45am -- that seems to make more sense to me as a timeline start but goes back to my lack of confidence in the "12:31" timeline.
2) 911 call. Likely from another room. It was certainly taken from whomever called, the call terminated, and possibly the phone damaged. Once the call is dropped, the recording is over. I agree this call led to the quick end of the event. If the perp(s) hadn't noticed then perhaps a different ending? Text to 911 is just getting rolled out; might have made a difference here, too.
3) Interesting items in that NBC article but the "James at the party" error was a doozy.
Trying to digest the newer info and I need to watch the Dryden interview for sure.