@dna I rewatched the film since. English with english subs. She definitely says "a little over a year ago".

@Tetsujin Thanks for that insight. I think Wikipedia is just citing the same in-universe newspaper in this case (as is HP wiki). But on-set experience is certainly valid.

Stanislavski's psychological theories were soundly disproven years ago. To say that modern method acting is still build on that is doing method acting a disservice.

@computercarguy While that happens a lot, a good number of actor-driven projects try to avoid it, as filming an emotional arc out of order is predictably difficult to feel your way through as an actor.

SPOILERS IN THIS COMMENT, DO NOT READ BEYOND THIS SENTENCE! Ariana died the fallout 3-way duel between Albus, Aberforth and Grindelwald. However, the blood oath thing must have been in place by then, so they could not have fought and she could not have died off a spell of which no one knew who cast it.

I'd say that adequately deals with the big one. The smaller one still confuses me, though, as Albus (book and this movie) seems a reliable source.

@DarthLocke it is based on facts in the film. It is part of a ... Second, more minor twist.

@F1Krazy She is credited with writing the script in the credits.

Though this is a good answer, I find it hard to accept because it still kind of goes two ways.