So far I haven’t been able to find any news coverage like this for Yasuko Endo. If we could find a television memorial programs like this perhaps there’s a chance that they played a clip of “In the Distance” or perhaps interviewed her managers or representatives from Pony Canon regarding when they decided to not release the single.
It’s unfortunate that there is no English wikipedia page for Yasuko Endo, (snip)
I. Here is a compilation of TV news reports about Yukiko Okada's death. Yasuko Endo is mentioned by name in the 4:51 and unnamed in the 7:37 mark. Possibly TV news reports also exist covering Endo's death.
***Here are some links provided by the user DurableNapkin on the Citypop Subreddit. They confirm that the master disc was created, and they where already printing copies of the single. It also confirms that promitional posters and single covers where printed as well. There is quite a bit of info here, and the names of a lot of people involved are in here as well. Theres a good chance of some potential leads in here, and here are the links:
(Keep in mind that these articles are in Japanese. If we could find someone to provide an accurate translation or summary of whats discussed, that would be an amazing help. I've been able to get bit and pieces from it so far, but there is a lot of info here)
(snip)
Based on machine translators, the idol-forever.jp links are chapters of a biography on Yasuko Endo (Table of contents, Wayback Machine link), with a chapter on Yukiko Okada (Wayback Machine link). I found on the table of contents the scan below which mentions "In the Distance" (encircled). [A copy of the scan without the circle is available here (Wayback Machine link).]
Notably, the biography does not contain a list of references.