So, what is supposed to happen at the end of the first film? Is that where the magic kiss is used? To bring Lois back to life?
IIRC, the original ending for the first film has Superman prevent one of the nukes from going off on Earth by throwing them in to space. I don't think Lois was ever supposed to be killed.
That nuke then allows Zod and co to escape from the Phantom Zone, completely replacing the entire Eiffel Tower sequence from the Lester cut.
The reverse time ending was always supposed to be the ending for Superman II but the pressure on Donner to get the first film finished (and to stop spending the Salkinds' money) some meant that he ended up using it for the first movie instead.