I haven't heard anything official on this topic, and I don't know if there is or isn't anything official about it. That said, what characters from Caprica do you think might get a chance to have an appearance in "Blood and Chrome" (aside, of course from William Adama). I certainly realize that they may not include any of them, or if they do include them they may be just background characters or bit parts.
Here are my thoughts:
Joseph Adama -- Almost a certainty in my mind. After all William's old man may want to see his son off to war.
Lacy Rand --Spoiler:
Daniel Graystone -- After all the Cylons are a Graystone product. Also Battlestar Wiki suggests that the First Hybrid might be Daniel himself.
Zoe Graystone -- She is the first so she might play some kind of role.
Anyway, those are the characters I think that might plausibly be in "Blood and Chrome." Again, I don't know if they will or won't be, but I think they ought to.