Ah, "The Vampyre". I read that years ago.
I think those two would work rather well along with the likes of Bathory, Olrox and Carmilla.
They are contemporary for the time of CV2, most of them being rather young vampires makes them perfect as bosses.
Olrox would be the elder vamp as he is a derivative of Dracula himself.
Elizabeth Bathory having died in 1614 is the next eldest.
Varney was turned some time between 1653 ans 1658 because of the interaction with Cromwell.
Carmilla would likely be the second youngest given the portrait of her labeled 1698. Which is a bit late, but nothing says she couldn't have been turned prior to the portrait's commission.
Last that leaves Lord Ruthven, who doesn't seem to have a specific date associated with his turning.