Helaman 8

As Nephi related the prophecies and testimony of many of the ancient prophets concerning the coming of Christ, he also teaches concerning Christ -

"...he is God, and he is with them, and he did manifest himself unto them, that they were redeemed by him; and they gave unto him glory, because of that which is to come." (Book of Mormon | Helaman 8:23)

I have always believed that we have this earth is an integral part of the plan of salvation of those that live on the earth. I personally believe that this world was created spiritually for our residence as spiritual offspring in a pre-mortal existence in vision, President Joseph F. Smith saw that -

"Even before they were born, they, with many others, received their first lessons in the world of spirits and were prepared to come forth in the due time of the Lord to labor in his vineyard for the salvation of the souls of men." (Doctrine and Covenants | Section 138:56)

I believe than when Adam and Eve fell, so did this earth. I believe Satan being cast down was in this world and is part of the world of spirits described as "outer darkness" for Jacob taught -

"...For behold, if the flesh should rise no more our spirits must become subject to that angel who fell from before the presence of the Eternal God, and became the devil, to rise no more.
9 And our spirits must have become like unto him, and we become devils, angels to a devil, to be shut out from the presence of our God, and to remain with the father of lies, in misery, like unto himself..." (Book of Mormon | 2 Nephi 9:8 - 9)

And Alma taught that the wicked upon death -

"...shall be cast out into outer darkness; there shall be weeping, and wailing, and gnashing of teeth, and this because of their own iniquity, being led captive by the will of the devil." (Book of Mormon | Alma 40:13)

...or in other words, spirit prison in the world of spirits. I believe paradise and the world of spirits remains here for Alma suggested that upon death -

"...whether they be good or evil, are taken home to that God who gave them life." (Book of Mormon | Alma 40:11)

Home in my mind is where we have always been, home here on this earth. I also believe -

"...that the earth will be renewed and receive its paradisiacal glory." (Pearl of Great Price | Articles of Faith 1:10)

...and that this earth will be the home of Celestial Glory. We also know that at the time of the Savior's death -

"...there were gathered together in one place an innumerable company of the spirits of the just, who had been faithful in the testimony of Jesus while they lived in mortality;
13 And who had offered sacrifice in the similitude of the great sacrifice of the Son of God, and had suffered tribulation in their Redeemer's name.
14 All these had departed the mortal life, firm in the hope of a glorious resurrection, through the grace of God the Father and his Only Begotten Son, Jesus Christ.
15 I beheld that they were filled with joy and gladness, and were rejoicing together because the day of their deliverance was at hand.
16 They were assembled awaiting the advent of the Son of God into the spirit world, to declare their redemption from the bands of death." (Doctrine and Covenants | Section 138:12 - 16)

While as He did -

"...he preached to them the everlasting gospel, the doctrine of the resurrection and the redemption of mankind from the fall, and from individual sins on conditions of repentance.
20 But unto the wicked he did not go, and among the ungodly and the unrepentant who had defiled themselves while in the flesh, his voice was not raised;
21 Neither did the rebellious who rejected the testimonies and the warnings of the ancient prophets behold his presence, nor look upon his face.
22 Where these were, darkness reigned, but among the righteous there was peace;
23 And the saints rejoiced in their redemption, and bowed the knee and acknowledged the Son of God as their Redeemer and Deliverer from death and the chains of hell." (Doctrine and Covenants | Section 138:19 - 23)

I guess what I am leading to is the words of Nephi that the Savior must have visited the ancient prophets after their deaths saying -

"..he is with them, and he did manifest himself unto them, that they were redeemed by him; and they gave unto him glory, because of that which is to come." (Book of Mormon | Helaman 8:23)

Again suggesting that he did before visit the spirits in paradise more than once.