Renee O'Connor did "Déjà Vu All Over Again" and "Dangerous Prey".
Michael Hurst, who starred on Hercules: The Legendary Journeys and made several guest appearances On Xena directed quite a few of the better done episodes. In fact, he was such a recurrent director, that the cast and crew, (all the way up to the executive producers) started to call him "Cup-Of-Blood-Michael" due to his love of using fake blood, and penchant to want more and more. You can thank him for the episode "To Helicon and Back"; One of the most gruesome and violent episodes in both the shows history, and that of television.
Disowned Adaptation: Rob Tapert openly hates the Dynamite Comics arcs, which act as a Fix Fic to developments that Tapert supported and continually defends to this day. One interview also suggests he's annoyed that Dynamite simply procured the licensing rights and didn't request any consultation (as he makes a point of criticizing them for doing that with their Army of Darkness comics).
Dye Hard: Lawless and O'Connor are both natural blondes; Lawless dyed her hair black (on Hercules) then brown, while O'Connor dyed hers red for most of the show's first two seasons.
Flip Flop of God: Ongoing after the show ended. Mostly regarding the nature of Xena and Gabrielle's relationship. Of note, around the time of the finale, Lucy Lawless felt it was "more than friends" due to a particular scene. By the time of recording DVD commentaries, this opinion was reversed.
(Hungary) Roughly a decade later, Gabrielle and Xena came back on TV as Linda and Gwen.
Non-Singing Voice: Both Gabrielle and Callisto in "The Bitter Suite," and Gabrielle again in "Lyre, Lyre, Hearts on Fire" (although the latter counts as a subversion - Renee O'Connor is one of three performers who do Gabby's singing here, according to the soundtrack album credits!). Averted with Xena and Joxer in both episodes, Ares in the former, and Draco (and Amoria) in the latter.
Viral Marketing: In a very early example, in 1995 the show's website (itself unusual for a show at the time) featured an archive of e-mails between researchers working on "The Xena Scrolls".
What Could Have Been: A version of the script for "The Furies" would have revealed that Ares was indeed Xena's father (this was changed due to 1) not wanting Xena to be a half-god like Hercules, and 2) the Squick factor that would result from Ares' constant interest in Xena). The final version is ambiguous enough that some people assume this to be the case anyway.