The future son, Scott (Tom Eastwood), said he was born Dec 1985 ..but at the end when his mother walked in her & her mother's beach-home, she wasnt pregnant "yet" the paper reporting her German dad's death said Oct 10, 1985. Not a big deal for such an interesting flick but it seems like her mother had her ON TIME lol
You can't go by events that where established before the timeline was changed. All we do know is that Hans survived the war, he married Samantha, and they did have Jody. But since other dates - like their deaths - were obviously changed so can Tom's birth date. We don't know that Jody was born exactly on time. They most likely have no recollection of the events in the cabin since Jody only passingly exhibited deja vu in the Dairy Mart. So there really isn't a concrete fate stream that the characters had to adhere to in order to fulfill a more positive future - they just had to avoid key tragedies. The rest was flexible.
Hans was Samantha's father. Adam was Jody's father, so in the new timeline if Jody existed her mother (Samantha) would still have met and conceived with Adam.
I guessed since Jody didn't hook up with the robber guy, Tom wouldn't have been born. I think he understood this when he went after Hans, which makes it noble.
I think a better ending would have been having Kevin holding the shopkeeper at gunpoint and putting him through the redemption. Then it could have been implied that he got straightened out and further implied a possible future for Tom's existence.