"foundation of the world" can refer, of course, to the beginning days of this world, but "before" makes it sound like the plan of salvation was laid before this world was created.

However, if that is the case, then the whole thing that Ellen White writes often about, where Jesus and the Father clasp hands and Jesus promises to go down to be a sacrifice IF anything should go wrong, is all just a big game for them, or else Jesus (and the Father) really didn't know what was going to happen.

What do you think?

I think it's possible to say that the Father and Son made provision for sin both before and after Adam sinned.  It doesn't have to be a case of only one or the other.

To this end, it may be useful to consider some chronology.

The first quote below says that the plan of salvation existed from all eternity.

The second quote says that God foresaw the future existence of sin, but did not ordain that it exist.

If we look at Isaiah 14:14, it says that Lucifer desired to be like the Most High, and the third quote below talks about how the Father and Son bore long with Lucifer.

The fourth quote is a variation of what was posted at the top of this thread.  It appears to be a description of what the second quote talks about, that is, that the Father and Son were always aware that sin could enter, and the description in this quote is a revelation of how they "made provision" for this emergency.

Another way the second quote says it is that the plan of redemption was an "unfolding" of eternal principles.

So I think it's fair to say that the Father and Son planned for this situation, both in a strategic and tactical sense.

-----

(1)

The plan of salvation had its place in the counsels of the Infinite from all eternity. The gospel is the revelation of God's love to men, and means everything that is essential to the happiness and well-being of humanity. The work of God in the earth is of immeasurable importance, and it is Satan's special object to crowd it out of sight and mind, that he may make his specious devices effectual in the destruction of those for whom Christ died. It is his purpose to cause the discoveries of men to be exalted above the wisdom of God. When the mind is engrossed with the conceptions and theories of men to the exclusion of the wisdom of God, it is stamped with idolatry. Science, falsely so called, has been exalted above God, nature above its Maker, and how can God look upon such wisdom?  {FE 186.2}

(2)

The plan for our redemption was not an afterthought, a plan formulated after the fall of Adam. It was a revelation of "the mystery which hath been kept in silence through times eternal." Romans 16:25, R. V. It was an unfolding of the principles that from eternal ages have been the foundation of God's throne. From the beginning, God and Christ knew of the apostasy of Satan, and of the fall of man through the deceptive power of the apostate. God did not ordain that sin should exist, but He foresaw its existence, and made provision to meet the terrible emergency. So great was His love for the world, that He covenanted to give His only-begotten Son, "that whosoever believeth in Him should not perish, but have everlasting life." John 3:16.  {DA 22.2} 

(3)

In great mercy, according to His divine character, God bore long with Lucifer. The spirit of discontent and disaffection had never before been known in heaven. It was a new element, strange, mysterious, unaccountable. Lucifer himself had not at first been acquainted with the real nature of his feelings; for a time he had feared to express the workings and imaginings of his mind; yet he did not dismiss them. He did not see whither he was drifting. But such efforts as infinite love and wisdom only could devise, were made to convince him of his error. His disaffection was proved to be without cause, and he was made to see what would be the result of persisting in revolt. Lucifer was convinced that he was in the wrong. He saw that "the Lord is righteous in all His ways, and holy in all His works" (Psalm 145:17); that the divine statutes are just, and that he ought to acknowledge them as such before all heaven. Had he done this, he might have saved himself and many angels. He had not at that time fully cast off his allegiance to God. Though he had left his position as covering cherub, yet if he had been willing to return to God, acknowledging the Creator's wisdom, and satisfied to fill the place appointed him in God's great plan, he would have been reinstated in his office. The time had come for a final decision; he must fully yield to the divine sovereignty or place himself in open rebellion. He nearly reached the decision to return, but pride forbade him. It was too great a sacrifice for one who had been so highly honored to confess that he had been in error, that his imaginings were false, and to yield to the authority which he had been working to prove unjust.  {PP 39.1}

(4)

Sorrow filled heaven, as it was realized that man was lost, and that world which God had created was to be filled with mortals doomed to misery, sickness, and death, and there was no way of escape for the offender. The whole family of Adam must die. I saw the lovely Jesus and beheld an expression of sympathy and sorrow upon His countenance. Soon I saw Him approach the exceeding bright light which enshrouded the Father. Said my accompanying angel, He is in close converse with His Father. The anxiety of the angels seemed to be intense while Jesus was communing with His Father. Three times He was shut in by the glorious light about the Father, and the third time He came from the Father, His person could be seen. His countenance was calm, free from all perplexity and doubt, and shone with benevolence and loveliness, such as words cannot express. He then made known to the angelic host that a way of escape had been made for lost man. He told them that He had been pleading with His Father, and had offered to give His life a ransom, to take the sentence of death upon Himself, that through Him man might find pardon; that through the merits of His blood, and obedience to the law of God, they could have the favor of God, and be brought into the beautiful garden, and eat of the fruit of the tree of life.  {EW 149.2}

Thank you all for your responses to this.

This quote shows clearly to me that the plan was laid after Adam sinned:

Sorrow filled heaven, as it was realized that man was lost, and the world that God created was to be filled with mortals doomed to misery, sickness and death, and there was no way of escape for the offender.  The whole family of Adam must die.

When Adam sinned, "there was no way of escape for the offender".  

I still wonder if somehow Jesus purposely gave up some of his omniscience when he created this world.

He even says that only the Father knows when Jesus himself will return again!