JOEL - According to the scriptures God gave us our agency and by putting us here on this earth gave us the opportunity to exercise that agency.
"The Lord said unto Enoch: Behold these thy brethren; they are the workmanship of mine own hands, and I gave unto them their knowledge, in the day I created them; and in the Garden of Eden, gave I unto man his agency; (Moses 7:32)
Behold, I gave unto him(Adam) that he should be an agent unto himself; (D&C 29:35)
So, I am not so sure agency was inherant with our eternal intelligences, but perhaps some agency was given to us after we were spiritually born in heaven. We must have had some form of agency in the pre-earth life to be able to choose between Satan and God's plan.
I do not think spiritual gifts were inherant with our intelligence either but are given to us by God during our life as a result of the influence of the Holy Ghost.(1 Cor. 12:1-12)
"And all these gifts come by the Spirit of Christ; and they come unto every man severally, according as he will.
And I would exhort you, my beloved brethren, that ye remember that every good gift cometh of Christ." (Moroni 10:17-18)
“And all these gifts come from God, for the benefit of the children of God.” (D&C 46:26)
Spiritual gifts come to those who have received the gift of the Holy Ghost. As the Prophet Joseph Smith taught, the gifts of the Spirit “are obtained through that medium” [the Holy Ghost] and “cannot be enjoyed without the gift of the Holy Ghost. … The world in general can know nothing about them.” (Teachings of the Prophet Joseph Smith)
Perhaps inherant in our spirits is the propensity to be able to receive and/or develope certain spiritual gifts different from what another person might have(Moroni 10: 8-16), much the same way we can discover and develop certain God-given talents that each of us have. Perhaps some of this comes with us from the pre-earth life where some of these gifts and talents were evident there. But most of the spiritual gifts are given to us while we are living here on earth.

TOM - I understand how the Atonement of the Savior is both conditional and unconditional but yet there is a question about the Savior's sacrifice that is interesting to me. It is commonly said that the Savior suffered the sins of all mankind but yet it also says that those who do not repent who have the Light in their lives must atone or repent for their sins themselves. Then it would seem that justice has been paid twice for the same sin in that instance. Joseph Fielding Smith seems to advocate that God did not suffer for the conditional sins of those who choose not to repent and have to suffer for them themselves and that is logical to me but that is not what is commonly said in the circles of the Church.

JOEL - God said:
"For behold, I, God, have suffered these things for all, that they might not suffer if they would repent; but if they would not repent they must suffer even as I; which suffering caused myself, even God, the greatest of all, to tremble because of pain, and to bleed at every pore, and to suffer both body and spirit—and would that I might not drink the bitter cup, and shrink" (D&C 19:16-18).
Noone can comprehend the degree of suffering that Jesus experienced to pay for our sins. Somehow His suffering was adequate to pay for an infinate number of sins committed by an unknown number of people who put into practice the principle of repentence, either during this life or for those who accept the gospel in the next life.
You can look at it two ways.
1. Christ's suffering was infinate and complete enough to cover all the sins of all people, assuming that everyone would repent of every sin. Which means like you say, unrepented sins will be suffered for twice.
Or
2. At the moment He suffered for our sins, it was somehow known in advance how many did or will repent for their sins, so that the degree of His suffering would match exactly with the number of repented sins.
I don't think anyone can really comprehend how it works. All we know is that the suffering He vicariously experienced on our behalf, is there for us to pay for our sins if we repent. Perhaps rather than trying to quantify it, we should think of it more like a light shinning through a window. You can place yourself in the light and enjoy its warmth, the joy of forgiveness, or you can stay away from the light and remain cold and dark, suffering for your own sins. Nevertheless the light will continue to shine and always be there for whoever is willing to go to it.

TOM - As Joseph Smith said that there is no substitute for experience and we all come to earth to get experience as even did our Savior. If those who die before accountability or otherwise are not accountable to any law or those children born during the Millennium who are not subject to Telestial Law then how can they get the experience of which there is no substitute?

JOEL - They will still get some experience during the Millennium, because life will pretty much go on as normal (Isa. 65:21-22), except of course that Satan will be bound so that no one will be tempted to commit sin(1 Ne. 22:26; 4 Ne. 1:15). The experience they will get with both good and evil will come at the end of the Millennium.
Both ancient and modern prophets foretold that, at the end of a thousand years of peace, Satan would be loosed, sin be introduced back into the world, and the final battle between good and evil would be waged (Rev. 20:7-8; D&C 43:31). It is during this time that Satan is loosed where all those you speak of will get their experience and opportunity to be tested and choose between good and evil.