One thing I noted, however, is how few of those quotes are in scripture. That means the majority of the text, and therefor your conclusions, are not based on canonized Church doctrine. As such, all of it is subject to scrutiny.

"Watch and pray, that ye enter not into temptation: the spirit indeed is willing, but the flesh is weak." - Matthew 26:41, (see also Mark 14:38)

• They ordained "in a manner that thereby the people might know in what manner to look forward to his Son for redemption" (13:2)
  
  
  • The word manner is defined "a way of doing, being done, or happening; mode of action" dictionary.reference.com
    
  • So, the priests were ordained "in the way it is done that thereby the people might know in what way they are to look forward to his Son for redemption"
    
  • So the way that priests are ordained is a symbol teaching us about the mode and manner by which we are to look forward/backward to the Son for redemption.
    
  • Redemption is a fundamental component of the atonement. In this case, we are learning about the eternal nature of the atonement and its ability to extend backward through time. He is trying to explain how it can be that the guilty are able to gain forgiveness and receive the blessings of the worthy before the atonement of Christ had happened. Rather than extending the timeframe prior to the atonement only to his day, (82 years before Christ), he took it all the way back to "the Foundation of the world" when we were all spirits prior the completion of creation.
  
  
• By the time the world was founded some had already shown, "exceeding faith and good works; in the first place being left to choose good or evil; therefore they having chosen good, and exercising exceedingly great faith..." (13:3)
  
  
  • In the pre-mortal spirit world there is opposition. That opposition exists in all things is evidenced by 2Ne. 2:11. This would indicate that opposition exists from the very beginning and as spirits we were able to choose, (according to our own progression and ability to chose), between these opposites, including the Good from evil.
    
  • Choosing evil we would either sin or transgress or simply make mistakes depending on our progression, knowledge and free will/agency.
    
  • Sins would make us unworthy of the blessings of the worthy including the priesthood. As his point is to explain how we can have and maintain the blessings of the priesthood being unworthy on our own merits, this is important to understanding his point. His point also shows us how we can have and maintain all the blessings of the worthy while not being perfect on our own merits.
  
  
• They "are called with a holy calling, yea, with that holy calling which was prepared with, and according to, a preparatory redemption for such." (13:3)
  
  
  • The calling to the priesthood is considered "holy" and given to those who qualify as "Holy"
    
  • The "holy calling" was "prepared with and according to, A PREPARATORY REDEMPTION" for those who are called...

1. What is a preparatory redemption?
   • What does it prepare us for?
     
   • What does it do for us in preparation for the thing that it is preparing us for?
   
   
   
2. As Alma is speaking regarding those who are called to the priesthood, both in this life and also in the pre-mortal life, who is he talking about? Who received the priesthood in the pre-mortal life?
   
   
3. Who can receive the priesthood in this life? Are any exempt such that they cannot benefit from this preparatory redemption?