Re: Capt. Pike and Matt Decker: did they serve on same vess
Not only did they serve on the same vessel, but they were lovers.
If you take a look at some of Roddenberry's notes to "The Cage," you'll see that it was his intention to make Decker the captain's yeoman, responsible for keeping the captain happy in every way. NBC nixed this idea as being far too progressive for an audience in 1964, and instead had him replace Decker with Yeoman Colt, and to suggest that while Pike was heterosexual, he was too married to his job to pursue any romantic or sexual entanglements.
There was an in joke on the set during the filming of "The Doomsday Machine" when Decker "penetrated" the planet killer with the shuttlecraft, since all of the cast and crew knew about Roddenberry's original intentions for this character.
If you look at Kirk's face at the precise moment when Decker enters the planet killer, you'll see that Shatner is actually making a "I just received a shuttle up the ass" look, which cracked up the filming crew so much that they had to shoot the scene a record 25 times.