I will share something here that I am not at all proud of and I have not read further in the thread so I'm building kind of off of what you are theorizing here. I'm completely with you. As you guys can tell by my posts, I have a young daughter who's 5 and I'm also I single mother. It's hard enough with my background and education to keep 'it together' at times and I know that the times when I have really been angry with my daughter or frustrated to the point I have almost walked out of the house, is in the middle of the night when I'm trying to sleep and she wakes up in some fit or doesn't want to sleep. Could be that I have a big day the next day or that it was a late day the day before but there have been times where I'm disgusted at myself for how frustrated I allowed her to get me. I have never hit her or did anything physical to her but I've gotten angry and raised my voice and sometimes walked away slamming a door because I just don't know how to make her calm down (clearly that's not the way.) Much of this was happening when I lived in Hamburg at a horrible job that was beyond stressful and I realize now that she sensed my stress and it reflected back to her. In the middle of the night when I'm half awake, half asleep, I have zero patience and when there has been tantrums or crying fits in the middle of the night like this, I wake up the next morning and feel HORRIBLE that I got so angry. During waking hours I am probably TOO patient with her. I'm glad this is over now, or seems to be.
But at any rate, kids sense the lack of stability and frustration in the mothers and NOW, to carry it further, add some drugs in the mix. Did AS black out (or SK for that matter) and they don't remember what happened to Elaina? Was she trying to sleep and became frustrated that the baby was fussy, which I imagine she was being on a floor in a strange house? If AS was 'high' and partying and the kids were fussy then I imagine that was a huge inconvenience to her. And back in the previous post where the Investigator says he can't talk about what the four year old has said, I would bet it is about how Elaina was acting or if the Mom got angry with her.
While it's of course possible there were no drugs involved, this is my opinion putting everything together. Who was AS talking to on the phone that day on the porch (or texting?) Was it SK or JK or someone else? Why did she need to go to the SK house if she could have stayed with her step-father? And if drugs were not involved, was this a setup on her part to point the blame at the K family? Better question too, what motive would SK have to harm the baby if they were broken up and she wasn't even normally staying at JK's house?
One last thing, do they drug test when you're arrested? Was the mother possibly drug tested and tested positive for something?