First off, welcome Misoka! You bring up some good possibilities.
re: McCoy, I doubt they'll explore much of his early life beyond mentions of it, but not a lot of actual screen time.
I think the safest bet in your list might be Carol Marcus, since she exists in this film's reported timeline somewhat prominently in Kirk's private life (not necessarily his professional career), and then nowhere else again until ST II with it's important revelation.
T'Pring's a possibility though that might get time consuming to delve into. So far we have no clue about Chapel's involvement or lack thereof. We'll have to wait and see on it all. But nice first posting, very relevant discussion topic!
MISSION:TREK's in-depth review of STAR TREK
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