[[WMG: Zeta is partially made from TimeLord technology.]]
After his first appearance in WesternAnimation/BatmanBeyond, Zeta was somehow damaged to the point that he regenerated, explaining why he looked different in this show. Since the [=TARDIS=] can regenerate, why not a robot made from similar parts?
[[WMG: Zeta is not the first Infiltration Unit.]]
Zeta is the sixth letter of the Greek Alphabet. His successor being named Infiltration Unit 7 gives further credence to this. Perhaps the show's premature cancellation is the reason we never saw Infiltration Units Alpha through Epsilon. If one of these earlier units was reprogrammed by terrorists, then the NSA's paranoia towards Zeta may be somewhat justified.
[[WMG: Agent West is related to the Flash]]
He's a lighthearted, eager to prove himself, a redhead and voiced by Michael Rosenbaum. He's either Wally's son or grandson who had no powers and joined the NSA in order to prove himself to his family.
* Orin has red hair... and BrownEyes, like Wally's wife does.
* It's unlikely anyone in his family would look down on him for not having superpowers, especially since Wally was shown to have as much respect for Bruce as he did for the superpowered members of the League. Given Orin's personality it seems more likely he joined out of genuine altruism and wanting to do good. Remember that while from the viewers POV the NSA are the main villains, in actuality they're a nationwide force attempting to keep the country safe from terrorists. He probably joined because he wanted to be a part of that, not to prove himself to his family. He's WrongGenreSavvy.
* Many of the Flash's early career personality flaws, such as over-enthusiasm and not thinking ahead before acting (before his CharacterDevelopment, of course) are core flaws of Agent West, who is about the same age in the NSA as his father/grandfather was at the start of his superhero career, give or take a view years. He's not out to prove himself to his family, his cockiness is literally hereditary, and he ''does'' improve over the course of the series. Given time he may be, in essence, the Flash in personality as well as looks, and just as competent in the NSA. He might also have been inspired by his lineage to help people, rather than the fandom interpretation of a bitter non-superpowered man.
* Being related to someone important would certainly explain how he hasn't been fired multiple times over.