#5 Start over. Do a movie set in the future, Terminators rule the world, the last of humanity in internment camps, ready for the dlaughter, hopeless. In comes John Connor rescuing everyone, including Kyle Reese. Start here, then skip to the end of the war for the rest of the movie. The film ends with Skynet sending back two Terminators. One to kill John's mother before he is born. A liquid Terminator to kill John as a boy in case the first Terminator fails. Kyle Reese is sent back to protect Sarah. A deactivated Terminator is reprogrammed and sent back to sent to protect John as a boy. Charges are placed, the time machine blown apart. The soldiers ask what happens now. John stares off into the distance as the screen fades to black, "There is no fate but what we make." Terminator music marches on.
I like that idea. But I think it would need to be made clear that it's set apart from the previous continuity.