Ayumi

It's most likely part of the drama soundtrack and will be included in the CD release (on sale August 27). They still haven't revealed the tracklist though so we don't know the title yet.
https://www.ponycanyon.co.jp/music/PCCR000000793

Same here! It makes watching this drama even more enjoyable.

It's probably a part of the OST and will be included in CD release (it goes on sale August 27).

No, not even a hint.

Coming to Prime Video (jp) on July 7.

Premieres next year
https://x.com/kazamakyojo/status/1926956483486392531

DVD release on August 8
https://x.com/gurame_tbs/status/1917413614257901592

We're getting season 2 in July!
https://x.com/TVGweb/status/1930384316946886774

Nope. Bromance at most.

It'll be shown at the Cannes Film Festival in May
https://x.com/exit8_movie/status/1910264376382435548

The special is set between the drama and the movie.

Tokai makes a comeback in the upcoming episode, exactly the same as he's been in season 1. The twins theory is more likely actually, what with Amagi's flashbacks of two kids holding hands.

No, 12 without the special.
https://x.com/umi_no_hajimari/status/1826169878971297911

Trailer https://www.youtube.com/watch?v=tD9Yejs_FWA

It might be referencing the flooding of Sayo town (specifically, Kuzaki district) in Hyogo prefecture in August 2009 (10 years before the events of the drama). Hyogo is in Kansai region, plus Kuzumi mentions everyone forgetting about it a decade later, which doesn't really apply to the events of 2011 but seems pretty in line with Sayo being a small and little-known town.
https://www.japantimes.co.jp/news/2009/08/11/national/flooding-devastates-hyogo-town-of-sayo/

Long trailer https://www.youtube.com/watch?v=1DpEbmNIhoU

Trailer https://www.youtube.com/watch?v=iueUTMI7Ai4

Teaser trailer https://www.youtube.com/watch?v=sjD47b6l1UA

Teaser PV
https://youtu.be/KPsqz57VdEE

It's going to be a movie https://twitter.com/k__u__n__y/status/1567571219968557056