I can't say "Happy Samhain". It just doesn't work. Nor "Merry". Happy or Merry is appropriate enough for all the other Sabbats, but not this one.
The best I've been able to come up with is "Peaceful". Wishing you a Samhain that is not crisis-ridden. Wishing you the Samhain symbolized by the Death card, not the Tower. May you get what you're looking for.