The four new Heroes and Villains will be Obi-Wan, Chewie, IG-88, and... some other Villain (Dengar? Tarkin? Boss? Veers? Who knows).
Mark this post
I think you're right on the mark about Chewie and Obi-Wan. Yoda was too old to fight by the OT era and Lando would be too similar to Han Solo to put him on the same side. R2D2 might add some well-needed balance to the hero side if they gave him his prequel flying abilities though, so I'm gonna say it's Obi-Wan and either Chewie or R2D2 for the heroes.
For the villains, they really need some more boring heroes to balance things out. Lando or Tarkin would do the trick, although Lando would only make sense as a villain on one map. (Cloud City)
I'd say the ideal line-up would be Obi-Wan and R2D2 (to balance out Palpatine and Boba Fett) and IG-88 and Tarkin. (to balance out Leia and Han)
There must be a balance! If there is Obi-Wan, there's gotta be another saber-wielding baddie.
The villain side is way overpowered (or at least way more appealing) right now. Think about this:
Heroes: a Jedi, a dude with a gun and a lady with a gun.
Villains: a sith lord with a lightsaber, a sith lord with force lightning and a dude with a jetpack and a flamethrower.
If anything the villains need more boring people to even things out.