The water gun that Teal'c shoots Daniel with was originally supposed to be empty, but was filled without Michael Shanks's knowing until he was actually squirted.
The location for the alien ghost town was the Plaza of Nations entertainment complex built for Expo 86. This location would also be used for the Season 4 episode 2010 (2001). The structure, originally intended to be temporary, was declared unsafe in 2006 and demolition began the next year.
In the 1986 MacGyver episode Nightmares (1986), MacGyver/Richard Dean Anderson is on his own, disabled, soon to die unless he can get the cure, pursued by enemies, and helped by a young girl who stashes him in an abandoned building; all of these things happen to Teal'c/Christopher Judge in this episode.
The insect has several similarities to the Iratus bug from Stargate: Atlantis (2004). Both have an armoured exterior and require other life forms as part of their lifecycle. Both have a virus associated with them which can rewrite human DNA. Differences are that this is a flying insect where the Iratus is more of an arachnid. Also, this uses people for reproduction and the Iratus uses people for food. It's possible both are connected on some level, or more likely that the Atlantis writers took some inspiration from the "Bane" insect.
Teal'c explains how the symbol on his forehead was created: The skin is cut with a special knife (called an Orak) that Jaffa priests use to cut the skin on the forehead and then pour molten gold on the wound on the Jaffa that will be First Prime.