Welp, that totally puts that whole train of speculation to bed.
To be fair, I suppose we do have to acknowledge that Vader-as-father only came in an early ESB script, and Leia-as-sister only existed as an idea for ROTJ, so Star Wars does kind of have this ‘laying the tracks before the train’ approach.
But still, I don’t think that justifies this lack of oversight and planning for what should have been a cohesive trilogy from the start.
EU media will gradually embed Palpatine-as-grandfather in the canon more solidly, but personally I’ll always prefer Rey Nobody, especially knowing how little it mattered to the production team.