Probably just therapeutic for me to write this, so I didn’t have to imagine the kids burning up in the fire. Still, I liked the theme and the idea of how it gets perpetuated.

Interesting to twist as to why she left.

I kind of like the clever teenage spin, it adds a layer of ‘can they defeat the master plans of mom and grandpa?’ Though a note: this seems to imply mom had other boyfriends, and that the current one was in the house, though she distinctly left her husband behind in the prequel.
Also, while she clearly accepts them as ‘her’ children,there is an element of deception that runs deep, as deep as grandpa. Perhaps she is not their mother after all?? Perhaps it was all a set-up? Perhaps the time is now because.. well I’ve got ideas, but I’d better not give them away.