There are of course differences, since Christ was conceived by the Holy Spirit and was both God and man. The Theotokos was not.
I'm not sure that I've noted that the Fathers speak to this in detail, since it enters the realm of theological speculation: what would have happened if the Jews and Romans of Christ's day had chosen not to kill him? -- as they certainly had the free will to choose to do or not to do. Would Christ have eventually died of old age and then been resurrected? Again, pointless theological speculation, which isn't really part of the Orthodox way of doing theology.
I don't think that it is safe to say that Christ's pre-Resurrectional body was incapable of corruption -- it obviously wasn't. He suffered thirst and hunger, he suffered pain, he bled, he sweated. None of these things are characteristics of a glorified body. In fact, if his body weren't just like ours, then he wouldn't really be truly God and truly man.
There are many, many stories in the lives of the saints where saints voluntarily die at a time that seems to be of their choosing -- in perfect concordance with the will of God. They are destined for death, are ailing, but to a certain extent are able to receive communion, say their last words, and then give up their spirit to God.
I have no problem in believing that something of this sort happened to the Theotokos -- I believe she probably did exercise some will to give up her spirit at the end of her life. But she knew the end was coming and inevitable, so this control was not absolute.
Christ, on the other hand, controls the winds and waves, and is the creator of the universe. He raises the dead, heals the sick of every infirmity, and told his disciples at the time of his Passion that he could call down legions of angels to aid him if he chose. In short, Christ could have chosen, so to speak to heal himself and continue to do so indefinitely. In that sense, Christ did voluntarily die, and the Scripture says that he gave up his spirit. The soldiers were surprised that he was already dead.
But he was born with a body that was just like ours. He also was tempted in every way that we were -- and it was real temptation -- otherwise how is he fully God and fully man? The Scriptures simply say that he was like us in all ways except that he did not sin.
The Theotokos didn't sin, and yet suffered the effects of "original sin" -- she grew old and died. I've not heard it said one way or another whether the Orthodox Church believes that Christ was born with "original sin" in that sense -- i.e. the tendency to death and corruption. This is probably because we aren't focused on original sin.
"Again, pointless theological speculation, which isn't really part of the Orthodox way of doing theology."
!
After all, He changed -- He grew from an infant into a Man in His 30's!
Adam was born without sin, but he was capable of corruption, and it was his sin that killed him. If we say that Christ was capable of corruption but not of sin, then He was not just like Adam. Unless He chose not to sin, but could have, just as Adam, then we can's peak of HIm as being "fully man" but a "superman." Just as the Theotokos becomes "superwoman" through Immaculate Conception, and therefore something more than "just human."
Christ, however, became Incarnate using Mary's flesh, which, as we noted, was afflicted by the consequence of the "original sin" (corruption and death), even though she her self did not commit any sin. So, His humanity should have been the post-fall humanity were it not for her to be cleaned of all sin, including the "original sin" — i.e. made "full of Grace" — at one stage in her life, in order to become a fitting vessel. But, if she did not sin since that moment onward, whether it was at her own conception or at the moment of Annunciation, she too would have been immortal! Which may explain why St. John Chrysostomos may have hinted at scriptural evidence that might show that she did sin after being made "full of Grace."
Finally, if God willed to die for His own reasons on the Cross, whereas He would not normally die, then He willfully ended His own life, and this is something we are taught is a sin.
I am sure there are sophisticated writings on this issue somewhere, but the Church hardly ever talks about these somewhat puzzling and open-ended appearances.
Talk about throwing red meat to the loyal opposition! :) Indeed, what would have happened if the Jews and Romans had not used their free will to kill Jesus? I don't know, maybe, perhaps, THE ENTIRE DOWNFALL OF THE CHRISTIAN FAITH! :) OT prophecy would have been destroyed, and Jesus' own words would have made Him a liar.
My red meat argument would then be that either Jesus was super duper lucky for things to turn out the way they did in order to accomplish what the Father sent Him to do, OR, maybe it's possible that God actually had a hand in arranging that all the necessary things took place. Perhaps God was really in control of the entire situation all along. Does God gamble on His plan, or does He ensure it?
I don't think that it is safe to say that Christ's pre-Resurrectional body was incapable of corruption -- it obviously wasn't. He suffered thirst and hunger, he suffered pain, he bled, he sweated. None of these things are characteristics of a glorified body.
So, then all of mankind is thankful that Jesus made the free will decision to not sin? Jesus could have sinned, but lucky for us He didn't?
[About Jesus on the cross:] In short, Christ could have chosen, so to speak to heal himself and continue to do so indefinitely. In that sense, Christ did voluntarily die, and the Scripture says that he gave up his spirit.
Now you're talking! :) The only addition I would make is to say that in EVERY sense Christ did voluntarily die.
The Theotokos didn't sin, and yet suffered the effects of "original sin" -- she grew old and died. I've not heard it said one way or another whether the Orthodox Church believes that Christ was born with "original sin" in that sense -- i.e. the tendency to death and corruption.
From my side, part of the answer would be that Jesus was never subject to growing old and dying of natural causes. He never had a tendency toward death and corruption. His mission and its accomplishment were perfect and complete from the beginning of time.
From my side, God did not rely on choices by men. Through withholding of protection and the causing of good, God's perfect plan was accomplished then, just as it is accomplished now.