The character that eventually became Vic Fontaine was written for [?] Frank Sinatra Jr.. in Season 4. Sinatra, despite being a fan of the show, turned it down, declaring that he only wanted to play an alien. After meeting with Robert GouletRobert Goulet, and attempting to get [?] Steve Lawrence, Tom JonesTom Jones and [?] Jerry Vale, the producers eventually decided on James DarrenJames Darren in Season 6. Darren would go on to appear in 8 episodes, including the series finale.
The subplot of Kira carrying the O'Briens' baby was to explain away Nana VisitorNana Visitor's pregnancy.
The guy who is often in Quark's bar is named "Morn", which is an anagram for "Norm" from [Cheers], who was often in the bar.