"Rejoined" is correct. When that other thread started about the probe in "Rejoined", I thought that someone would get the answer right away.
Note: the post with clue six contained a typing error (cook-->cool) that I fixed a little bit later. I hope it had no bearing on the outcome. Sorry.
All clue explanations:
#1 Lenara's brother is concerned about reassociation.
#2 The short-lived artificial wormhole is an important breakthrough.
#3 Eddington, whom some consider a traitor, was on the Defiant during the experiment that had problems.
#4 Worf at the reception explaining Klingon dreams was a joke, perhaps.
#5 Jadzia and, later, Julian perform magic tricks.
#6 The force field Jadzia uses to get to Lenara looks like a slide, and Jadzia cautiously makes her way down it. Opinion: it would have been cooler if she had slid down it.