Perhaps a long shot, but might it be possible it was the core WarioWare creative team (Goro Abe, Ko Takeuchi, and the Paper Mario team of Intelligent Systems) that pushed for this to be released and/or made the trailer? Perhaps the same Wario...
I've said this before and will say this again: Princess Shokora would make a great Fantasy genre stage host. Her comparatively straight-laced nature even in cat form would contrast well against the trouble Dribble and Spitz find themselves in.
Piecing together the page's history from Wayback Machine, it shared the same Under Construction page as the Aroma Button until the Jan 2024 final update. Only after that update did the page get retooled to the joke a holiday form we see today...
Mayhap if only Wario got his labour thanksgiving for trying to finish the website, would this page be finished.
Although this holiday is only penance for me missing out on Shichi-Go-San, which I don't think has ever been seen in its full glory...
If anything, WarioWare games (well, the normal modes) are characterised by their strong lives systems (where boss microgames means you can lose at most one microgame per cycle without being life-negative), whereas Wario Land games past II are...
Since Halloween 2025 is unchanged from last year, here's a throwback to a Reddit post which arguably was where it all began; when it became more common knowledge that the contact page is more seasonal than expected.
As an aside, I've no idea...