Your 4 points make it sound like they besieged the home, like the Jamaican druglords did to Ox in Belly. The CNN article says that they were there for "her birthday". It's still unclear whose birthday that is, but I read it as the foster mother's. So that gives them a legitimate reason to be there.

The foster mother also says the argument was about the girls keeping the house clean. That's a fairly innocent start to a brawl. Why would the 28 year old, who's there to celebrate a birthday, decide to pick a fight?

Again, I don't think resting your argument on a string of ifs and maybes, which all break in Ma'Kiyah's favor and all paint the 28 year old as some some of villain is a good thing to do.