Temple Sealings - What are they for?

I had a "professor" of religion in college who quoted some obscure reference from an early apostle that implied that God was Adam's literal father. I had issues with that, particularly with the idea that there were now two only begotten sons of God, but I don't want to get into that. Suffice it to say that his biggest justification for that being true was the fact that we needed to do temple work for all of humanity, tying us to our parents and they to theirs and so on, back to Adam and Adam to God. Last night, Betsy and I were discussing temple sealings and I realized that adopted kids are sealed to their parents but are not begotten by their parents and it is entirely possible for Adam to seal the rest of humanity to God without being the literal offspring of his diefic flesh. I'm not going to evaluate whether he was created out of the dust of the earth or not at this time.

Hebrews 11:40 - God having provided some better thing for us, that they without us should not be made perfect, speaking of the people who had died having great faith. They did a lot of great things, that demonstrated their faith, but without us, they can not be made perfect. Of course, the JST changes it a bit and says that without their sufferings they could not be made perfect, but then it cross references topical guide, geneology and temple work. Why reference that if the JST just made it irrelevant?

D&C 27:5 - Moroni has the keys of the record of the stick of Ephraim. In what way would priesthood keys be necessary for a record? In my understanding, keys in the priesthood are essentially right to authorize ordinances and receive revelation for a specific group.
27:6 - Elias has keys of bringing to pass the restoration of all things. Apparently I've misunderstood keys.
27:7 - Says that the angel that appeared to Zacharias was "Elias". Luke 1:19 says that the angel said, I am Gabriel, that stand in the presence of God. What are the odds that Gabriel was the Elias on the Mount of Transfiguration?
27:8 - Which John I have sent unto you...to ordain you unto the first priesthood...that you might be called and ordained even as Aaron. Ordained so that you can be called as was Aaron? The calling happens because of the ordination, not the other way around?

D&C 27:13 -