Maybe we'll get to see their orginals in kh3. They've been spanning out occurrences of them through out three series so maybe they will appear in kh3.
I don't think Eraqus will come back mainly from the fact that Eraqus was killed. I agree with on Xion. If roxas is coming back than so is namine, because they both returned to they're originals, cause theyre hearts are still in there. Well I we'll see when it comes out.