In the episode "Stranger in a Strange World," it clearly establishes that if you die in one world, you die in the other. With that in mind, how is it possible to Iolaus 2 to survive after the death of Iolaus in the Season 5 premier?

For someone who was paying such close attention in "Stranger in a Strange World," you totally ignored the explanation in its follow up episode, "Stranger and Stranger." Iolaus 2 survives because, at the time of Iolaus' death, he was "in the world between worlds," and thusly, was not affected by that rule.

So, why ARE there two Deianeras?

The answer is not nearly as complicated as one might want to make it seem. The simple answer is this: there were two Deianeras because Hercules knew two women named Deianera. The character played by Renee O'Connor in The Lost Kingdom is not that same character that Hercules later marries.

The movies state the Iolaus has a wife, but she is never mentioned again, what gives?

The movies are what I consider, a "loose canon." The events of the movies DID takes place, but maybe not exactly as we saw them. The plotline of Iolaus being married was dropped when the movies became a TV show, but the basic gist of the stories, such as Hercules getting married, remained.

Kevin Sorbo talks about a 7th season in his commentaries, but I only have 6! What happened to the final season?

Kevin Sorbo had always looked at the tele-films as the first season of the show. When Anchor Bay released the DVDs though, it combined the movies with the "first season," and as a result, created six total seasons.