Michael Shanks (Daniel Jackson), Amanda Tapping (Samantha Carter), Christopher Judge (Teal'c) and Gary Jones (Walter Harriman) are the only actors to appear in both the first and last episodes of the series: Stargate SG-1: Children of the Gods (1997) and Stargate SG-1: Unending (2007).
It's what we do...
The IOC ( International Oversight Committee) as explained makes little sense. The US can clearly afford to maintain the Stargate program and giving countries which might someday be enemies of the country access to a technological advantage could threaten national security. While it was done to give the series a broader appeal, overall the ideas behind it don't match up with the logical flow of the narrative. However, considering the vagaries of international diplomacy, it is certainly possible.
The syndicated version of the episode "Within The Serpent's Grasp" does not include O'Neill's quip about whether the Gou'ald long range visual communications device can pick up Showtime.