EXCLUSIVE: Nathaniel Arcand (Cold Pursuit) has been cast opposite Julian McMahon, Alana de la Garza, Keisha Castle-Hughes, Roxy Sternberg and Kellan Lutz in FBI: Most Wanted, the planted spinoff of Dick Wolf's freshman CBS drama series FBI. The spinoff has a series commitment, making an episodic pickup for next season likely. As the name suggests, FBI: Most Wanted centers on the division of the FBI tasked with tracking and capturing the notorious criminals on its Most…