One point. I don't think Minato is required to access the Yin chakra. According to Sandaime, Minato and the Yin are locked in eternal combat in the belly of the Death God. If the Yin were merely sealed within Minato through the Dead Demon seal, then such combat would not be feasible.
My conclusion is that the DDS is merely a way to entrap the Person or thing that is being sealed so that both the Sealer and the Sealed may then be drawn inside the Death God. Once inside the Death God, they are released to begin their eternal combat. I therefore think that an uber Geddou is all that is required to draw out the Yin, Assuming that the Death God can even be violated in this manner in the first place.