[X] Tell the passengers you true destination, it's bound to come out sooner or later, and that way they can make an informed decision about either Volantis or Lorath.
-[X] If mutiny or unrest does happen, hear their cries and try to settle it peacefully. You have, after all, saved them from a Dothraki horde that was about to raid the city.
[X] Don't tell them. The whole point is that no one can know where to find you. You want to keep it hidden until you arrive in Volantis. If you lose some people because they can't handle the secrecy of an unknown destination, so be it.
-[X] If anyone tries to start a mutiny just calm things down and remember them that they could be facing the dothraki. Instead they are in your boats safe from the savages. The least they can do is follow your instructions.