Events changed by the arrival of Kyle
Notes on Chronology 3
We cannot be certain that Kyle becomes John's father at this point. One of the dynamics between Sarah and Kyle in Terminator is that Kyle was in love with Sarah before he volunteered to return to protect her. This love was for the legend... the great Sarah Connor and based in part on her photograph. Here it was Sarah herself sending Kyle back so we are not certain what the relationship between the two is. However, this is the earliest Chronology in which Kyle can become John's father, and so we include it here.
When Sarah was locked up in Pescadero, John was told she was insane. He no longer believed the stories she had told him about Kyle, the Terminator, Judgment Day and her role as the great military leader. He thought it was all "made up bullshit".
When Judgment Day occurred, John had to realize that his mother had been telling the truth. We do not know if Sarah managed to escape from Pescadero, but we can assume that she did not. In Judgment Day the police share with her the knowledge that a T‑800 is around, show her photographs from the encounter at the Mall, and tell her that her son's foster parents have been murdered. As this is Sarah's motivation for escaping and these events do not occur here, we can assume that Sarah does not escape, or at least not at this time. So, it is possible that Sarah is still in Pescadero when Judgment Day happens. Even if Sarah does escape, there is a possibility that she and John never get back together.
Additionally, John must realize that the date for Judgment Day that Kyle told Sarah, almost certainly after 2004, was incorrect. It actually occurred in 1997. This causes John to understand that changes are being made to the past, that by visitors arriving from the future, events are changing. Not only are they changing, but they are changing for the worse, Judgment Day happened years earlier than it otherwise would have. This causes John to realize the power he - and Skynet - have to change the past.
Also, we see that Kate and John meet in 1994, but we have no idea how they eventually get together to form the resistance. Because John's foster parents are not killed in this sequence, John and Kate may have become a couple at this time and continued on until after Judgment Day, or they may have lost touch and then reunited at some point.
There is a hint in Rise of the Machines when the T‑800 says that through Kate's father John makes contact with members of the military and John says that if he had not disappeared, because of the T‑1000 and the murder of his foster parents, he and Kate would have gotten together back in 1994 and he would have met her father then. So we can assume that is what happens here. John and Kate become a couple, John meets Robert Brewster and, through him, makes contacts with the military that he uses after Judgment Day to build the resistance.
One shocking point is that Sarah dies in this sequence. Again, as with Kyle fathering John, we do not know that this occurs in this Chronology, but it eventually occurs and this is the earliest point at which it can and so we include it.
One of the ways you can get leukemia is through exposure to radiation. The only exposure we know of is when Sarah crushes the T‑800. We learn in Rise of the Machines that the T‑800 is powered by a hydrogen fuel cell. In crushing it, Sarah gets exposed which leads to her leukemia and death. We do not know if she dies in 1997. In Rise of the Machines we learn that she "held on" for three years to ensure that Judgment Day didn't occur. Here, though, she does not expect Judgment Day to occur in 1997 and she has lost contact with John.
This also explains a troubling quote from Terminator. Kyle is talking to Sarah at the Tiki Motel about the photograph John had given him. "You were young, like you are now". If Sarah dies in 1997, at age of 32, where and when did Kyle see her when she was not young? In Judgment Day, just three years before her death, Sarah does not look that much older than she does in the photograph. However, with Sarah developing leukemia, she may have gone through chemotherapy and there must have been a photograph taken of her when she did indeed look older.
The only other explanation would be that Kyle saw her when she was actually old. As he was not born until after Judgment Day in 1997 and Sarah dies in 1997, she must not have died. This would require some very convoluted logic and so, by Occam's Razor, we discard it as possibility. Note that this "aging" via chemo may also be why Sarah's friends put the birth date of 1959 on the plaque on her crypt, not knowing her age, they simply guessed.
We do not know if John and Sarah have any contact after her incarceration so it is possible that John does not even know of her death. In fact, he may not know of her leukemia. When John joins the resistance, Sarah is not around. He sees again that Kyle's report of the future is wrong or that events have changed by visitors from the future.
Another interesting note is Kyle tells the police that after he had been sent through the time-displacement device, it was going to be blown up.
Connor sent me to intercept and they blew the place ... nobody goes home. No one else comes through. It's just me and him
Obviously others do come through so the question is, did Kyle know this and was lying, or was Kyle lied to, or did Skynet build another device?
Finally, let's ponder for a moment the major changes wrought by Kyle's arrival. John comes into existence for the first time. Kyle dies and Sarah dies. This future will be very different than those before. The Terminator succeeded in its mission, it killed Sarah, but not before a replacement leader was born and trained - the great John Connor.