Current status of my investigation of the connection, if any, between “The Naked Time” and “Tomorrow is Yesterday”:
The early draft of Naked Time is called “The Naked Time, Part I” and has the Enterprise heading to Earth at the end of the episode - per this The Naked Time
D. C. Fontana (the credited writer for “Tomorrow is Yesterday” says that Naked Time was at one point intended to connect with TiY (- YouTube)
“These are the Voyages, Vol 1” by Marc Cushman, which has a foreword by John Black (the writer of The Naked Time), also cites Fontana in reporting that the Naked Time and TiY were connected at one point (it also notes the striking similarities between a memo that Bob Justman wrote, outlining a story idea that sounds a lot like TiY, and not mentioning The Naked Time).
“Inside Star Trek” by Solow and Justman go into more detail about how Justman’s originating of the idea for TiY, and does not discuss any possible connection with the Naked Time.
My conclusions:
- It looks like Fontana took Justman’s idea for TiY - possibly at Roddenberry’s direction.
- Justman didn’t intend any connection between his idea for TiY and any other episode
- It looks like Fontana did think about connecting Naked Time and TiY at some point around the time that Black was writing the first draft of Naked Time (Justman wouldn’t know about what Fontana was thinking).
YMMV - but at least it’s clear that I’m not repeating a fan-myth.