Re: So you're commissioned to write an actual Star Trek book...
DS9 - During a festival that remembers and honours the dead, the station inhabitants are visited by friends and family members who have since passed away.
VOY - Voyager
is hit by an unknown energy wave that causes the crews memories and personalities to switch into the bodies of those nearest them.
Avatar: Captain Naya, U.S.S. Renown NCC-1415 [Star Trek: Four Years War]
Manip by: JM1776 (STPMA.net)