>>32283204No really, if Stoutland died or not is anybody's guess really, unless we, for whatever reason, see it again in the future.
That the anime won't have the UBs in an arc is still up in the air, they could be both in the movies and an anime arc.
Necrozma appearing in a movie makes sense considering its dubious status, also that they're doing this for the 20th anniversary movie doesn't mean every movie will take this approach from now on.