First off, he reports that actress Laura Vandervoort has been signed to play the part of "Lisa," a Visitor who is able to use her sexuality to manipulate both Tyler Evans and his friend, Brandon. Finding a counterpart to Lisa from the original "V," it would likely be the Visitor Brian, who makes Daniel Bernstein (David Packer), a neighborhood misfit, feel like he has a place to belong as a part of the Visitors; and manipulates Robin Maxwell (Blair Tefkin) sexually, going so far as to impregnate her (which in turn leads to the birth of Elizabeth Maxwell, the Star-Child -- admittedly too much info for this post). Vandervoort, of course, is best known for playing Kara (a.k.a. Supergirl), Clark Kent's Kryptonian cousin on Smallville.
Additionally, Alan Tudyk, Wash from Joss Whedon's Firefly and its feature film follow-up Serenity, is playing Erica Evans' partner, Dale Maddox, who is not what he appears to be. Tudyk, of course, had co-starred on Firefly with Morena Baccarin, who plays Visitor leader Anna in "V". Finally, as we suspected in an early post, Byrne confirms that Elizabeth Mitchell is indeed playing Erica Evans.