Except the delegation continues, as we also believe the pre-mortal Adam (Michael) assisted in the creation as well. Further, while I don't know what the official status of it is, I know that a common LDS belief is that we all helped, to some extent, in creating the earth. I think this is a cool doctrine. I like it and I believe it.
The atonement is seen, I think, as a very unilateral thing in general Mormon thought. Jesus took upon himself all our sins, guilt, pain, sorrows, and death, and overcame them all. The only thing we did to contribute was to sin or feel sorrow--not very helpful :) We can apply Christ's atonement by repenting and forsaking our sins, then God will remember them no more and we'll be cleansed. I love this doctrine and I believe it.
I wonder if there's something akin to our deeper understanding of the creation that could also apply to the atonement. Can the prophetic imagery of plural "saviours on mount zion" refer to more than just baptism for the dead? (I'm not saying it doesn't apply to temple work--it does--but I think there's more too)
I love how Abinadi teaches that when Isaiah says that Christ will "see his seed" when his soul is made "an offering for sin," that his seed includes all prophets and all the people who have looked to Christ for a remission of their sins (Mosiah 14-15). Abinadi, in effect, says that Christ saw us, his disciples, while undergoing the atonement--and the inference is that seeing us helped him go through with it. Knowing that billions of people had been waiting for the atonement for millennia, and also that billions more would in the future depend on it, was a source of power to him at that time of greatest need. That can motivate us to be worthy of that trust, to live better, more divine lives.
Further still, I think of Father Zosima from The Brothers Karamazov. He said "Each one of us is guilty before everybody for everything, and I am more guilty than anybody else." And again, "There is only one salvation for you: take yourself up, and make yourself responsible for all the sins of men. For indeed it is so, my friend, and the moment you make yourself sincerely responsible for everything and everyone, you will see at once that it is really so, that it is you who are guilty on behalf of all and for all. Whereas by shifting your own laziness and powerlessness onto others, you will end by sharing in Satan's pride and murmuring against God."
*I have no doubt but that Heavenly Mother was included in this direction, and that Eve and other daughters of God helped throughout the process too.