Bespin Gown Leia
Cloud Car Pilot
CD Rom Bespin Vader
I think these are the most likely of the bunch for a Bespin wave. Hasbro has stated that the themed waves would include approximately 4 figures, and that's 4 right there.
A Bespin wave certainly wouldn't seem out of place. Most of the themed waves for 2004 are slated to be from the original trilogy. Thus far with only five waves officially announced, I think a Bespin wave is very likely.
As for the Star Destroyer wave, it's entirely possible that Dengar isn't the only Bounty Hunter in the wave. 4-LOM has been silently calling for a resculpt. That POTF2 figure dates back to aroun1997, I believe. I also recall seeing a rumor of a resculpted Imperial Naval Trooper.
All I can say beyond this is wait. We'll probably find out more beyond wave 5 from Toy Fair in February.