I found the SM posts very saccharine, glossy. They reminded me of Jennifer Hart and her wife's post. She was the woman who drove her family off a cliff. She posted about her lovely family, and photographed them being lovely. In reality, they were starving and none of it was true.
I also read between the lines on the articles.
Being helpless at a German airport—and mentioning they had no way to communicate with Germans—seems like a step in the direction of "this family is going to find it very difficult in a foreign environment". Unresourceful. FWIW most Germans speak English. It's a required subject in school, and if your plane gets delayed, you flag down an airline employee or go to the ticket counter to get it handled. No need for German. Par for the course.
IMO DV or an affair. Garden variety except for the Angola angle.
It could have been a gun, a knife, or, I'm thinking, a machete. They are more common elsewhere than in the US.