The original Engineer of the entire Black box system is played by the same actor who played the Computer savant Laslo in Real Genius. The character of Laslo went into seclusion after some tech he created was misappropriated by the Govt to create a weapon.
For others, he's more recognizable as Broots, another computer genius.
Isiah Mustafa is Cyrus, a rogue Division agent turned arms dealer.
Truth in Television: The episode where Division attempts to kill a Georgian prince has a background in reality. There really is a Monarchist tradition in Georgia (though it's been absent from power for 200 years), and there really was a dynastic squabble settled by the two lines marrying recently, in 2009. All the personal stuff was fake, though.
Also, Nikita picking at her food in the suburban mealtime in 1x20 because it was a pot roast. She apologises when the kid says she is "busted". This is an allusion to Nikita's actress Maggie Q's real life veganism and animal activism. She is also well-known for ensuring that she works in places that do not use fur, and has changed this when working on certain projects before.
Retroactive Recognition: In "Alexandra," that's Kenzi as Alex's friend from her sex slave days. And then Lauren as a terrorist four episodes later ("Girl's Best Friend").