As they point out, these placeholder titles confirm the Clone Wars setting of these books, and also provide a firm indication that both writers' books form part of a coherent series.
We actually covered the solicitation for the Traviss audiobook a few days earlier, but I didn't really notice the significance of the "Clone Wars #1" title, as the evidence was already pointing in that direction.
As we noted in this?earlier?story, the release date for the Karen Traviss novel suggests that it will be the adaptation of the up-coming Clone Wars animated movie, and the first in a series of four tie-in novels for the movie and the TV series.
My suspicion is that Traviss and Miller are each writing two books in the series, but we'll bring you more news on this--and other Star Wars books stories--as soon as we get it ourselves.