Clue below if you're still looking. Indirect spoiler.
.
.
.
.
.
.
.
There's one that I didn't get until after the one outside the mansion that you mentioned, so I'm guessing it might be the one you're still looking for. Technically you could find this scene very early depending on how early you figure out all the mechanics of the curse.
I know that's extremely subtle, so I also have one more clue below.
.
.
.
.
.
Each person's final scene occurs in a time slot that includes a thunderclap. Do you have every thunderclap paired with someone?
And one last one, a bit more obvious below if you need it (but still not the direct answer).
.
.
.
.
.
Characters were identified by numbers to keep track of who was talking before we knew their names. Was there anyone who we never heard speak? What would their number be?
Hope these were helpful enough without being too obvious.