This episode establishes that Lena and Lex's father was named Lionel Luthor. This name was first used in Smallville (2001), in which Lionel was played by John Glover, and then introduced into the comic canon in the 2003 limited series "Birthright."
Though just as a child in flashbacks, this is the first appearance of Lex Luthor.
Lena Luthor was born in 1992.
The surveillance tape that showed Lena Luthor obtaining the kryptonite turned out to be a corrupted video that was altered by Hank Henshaw AKA Cyborg Superman. In the DC Comics series "Reign of the Supermen", Cyborg Superman was one of four super-powered heroes who appeared in the wake of Superman's death. The Cyborg was the only villain of the four and managed to convince the world that his Kryptonian Counterpart "The Last Son of Krypton" (AKA The Eradicator) was the true villain in the same way that Henshaw fooled the DOC. Henshaw's cyborg enhancements allowed him to manipulate video feeds to make the viewer see whatever he wanted them to.
It is mentioned that Clark Kent and Lex Luthor were best friends when they were younger. Which is what they were in earlier seasons of Smallville (2001).