The Zeta Project/WMG

Zeta is partially made from Time Lord technology.
After his first appearance in Batman Beyond, 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?

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.

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 Brown Eyes, 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 Wrong Genre Savvy.