Well, I do have some answers here too.
In fact, I've dedicated a part of my Kes Website to "Voyager Mysteries-and how to solve them" at
As for Tuvok, The Tuvok lookalike in "Starship Mine" is actually Tuvok's evil brother Devor, the black sheep of the family who have left his home, denied his relatives and became a criminal. For some reason, Tuvok has never mentioned anything about Devor (or Devok if you want it more Vulcan), maybe for the same reason as Spock never mentioned his brother Sybok to Kirk or McCoy.
As for the Tuvok lookalike in "Generations", let us just assume that it's Our Favorite Vulcan himself, on a brief stint with the Enterprise. Why not?
The Tuvok in the DS9 episode "Through The Looking Glass" was a mirror Tuvok.
Not to mention that he did show up briefly in an NCIS episode when he was transported back in time on some secret mission!
As for Chakotay and Chekote, there is a certain difference in spelling those names.