what happens after?
This one always trips me up. Given Grace seeming bad-ass at the end and winning and beating the whole family, as well as Mr. Le Bail giving her an approving nod, I feel like we're *supposed* to feel like she won, not only getting away with her life but also her freedom and gaining their fortune, since she's literally the nearest surviving kin. But that's only if it looks like everyone else burned to death. Which wouldn't be likely.
And with forensics, they'd be able to tell. Or would they? The mom and the brother are the only ones there *might* be anything left of to inspect post-fire, since the rest exploded and essentially disintegrated.
Plus the rest of the grounds would probably be searched as a matter of due course and they'd find the maids' bodies.
And, with her "not blue enough background," plus the truth being unbelievable, they'd be quick to "Gold digger murders entire family of in-laws on wedding night and tries to make it look like an accident" kind of thing.
I realize I'm over-thinking it but it's interesting to ponder.