Actually I've read that we won't see any cameos from the Bane books because of the time gap. So...not sure which way they'll go.
They did release the cover for #4 finally, basically the same as the Comic Con flyer they had, plus the synopsis:
Click here to see the hidden message (It might contain spoilers)
Kerra Holt has her Jedi work cut out for her! As crime lord Zodah the Hutt’s massive Stormbringer vessels flood Kerra’s homeworld with rain, she does her utmost to herd the listless inhabitants to the safety of higher ground. Meanwhile, Sith Lord Daiman doesn’t appreciate Zodah destroying a world that belongs to him! Soon, Kerra will have two armies to fight!