The Quinlan Vos scene was never even filmed, so the chances of it showing up on the DVD are somewhere below the Holiday Special getting rereleased.
Besides the aforementioned Birth of the Rebellion sequence, the one I most want to see is on Polis Massa where Qui-Gon's spirit voice is talking to Yoda before Bail comes in to tell him that Padme's giving birth. This is the major loose end I would have most liked to see resolved. I think the way this “revelation” was handled was the only major miscalculation in the ending.
As I understand the dialogue was never recorded, so I doubt it will be on the DVD.
I suppose it's possible, and ideally it would be edited back into the film proper, like the extended Podrace in TPM.
It would be cool to see Yoda land on Dagobah--and would be relatively easy to reconstruct for the DVD by pasting CGI Yoda and lander into an establishing shot from ESB--but it’s not essential. In fact, it helps to preserve a little of the surprise in the OT if you watch them chronologically. You know Yoda is hanging out someplace and should reenter the story at some point, but you don't know where