While Rube's cause of death is never outwardly stated, several of the second season episodes hint that on the night he was killed, Rube tried to rob a bank (the wanted poster Rube finds when searching for information about Rosie, and the gun he's constantly carrying around in his flashbacks).
The red frog that keeps appearing here and there through the series comes from the first scene of the pilot. It is, depending on who you ask, the first "person" to die, the first reaper, or both. The frog is an Argentinian horned frog (aka, "the Pac-Man frog"), which does not make sounds like North American frogs (during one take, however, the frog hissed when Ellen picked it up, scaring the daylights out of Callum Blue and Jasmine Guy), The "frog sound effect" is dubbed in. The Pac-Man frog also has sharp teeth, and should only be handled by professionals, as its bite is very painful.
According to Bryan Fuller (the show's creator and head writer for the first four episodes), it was originally planned that George's father would be gay, and this development would spell the end of Clancy and Joy's marriage. After Fuller left the show, the show's new executives decided that Clancy should be heterosexual, but philandering with his female students.
Although set in Seattle, the series is actually filmed in Vancouver, B.C., Canada. No effort is made to hide street signs, local business names (e.g., Avalon Dairies), etc., and in one episode both a Canadian flag and a B.C. flag are visible in the background.