There will be no Purist version of ESB (which won't have very many "controversial" changes anyway in my opinion) or ROTJ (which might anger some, because there's going to be a LOT of changes to ROTJ).
Since he's doing ESB in 720p, my bet is that there will be an H.264 HD release. ANH was done in standard-def, and a lot of the changes in there would have to be completely redone to make an HD release, and Ady has said he won't be doing that.