I rewatched Kate and Leopold today.
I just realized that the movie discredits or disproves itself.
So Stuart goes back and time and takes pictures and Leopold follows him to the future.
At the end of the movie Leopold goes back to his own time so he can invent the elevator and stuff. Stuart tells him that he’ll repeat somethings because he’ll be returning to the same day that he left. He urges Leopold not to “follow him this time.”
Then Stuart looks at his photos and he sees Kate at the party and realizes that she needs to go back in time too. So she does. She runs in right as Leopold is announcing his bride.
There are two major problems here.
First, the photo of Kate. Stuart took that picture in the middle of the party… Before Kate would have shown up.
Second, when Leopold returned to his own time, there would have been two of him running around (just when Harry Potter goes back in time in Prisoner of Azkaban).The first Leopold would be the one who followed Stuart and went through the time portal. The second would be the one who lived a week in the future and came back with new knowledge and new love. He couldn’t have just assumed the spot of his former self, because his former self had to fall into the portal in order for the latter to have been able to return and exist with all of his memories of the early 21st century still in tact.
The fact that Kate was in one of Stuart’s pictures proves illustrates that this film follows the same kind of time travel as in the Harry Potter world, in that there is only one version of the present. There is no going back and accidentally killing your grandfather, because if your grandfather had been killed before having kids than you would have never been born to to kill him. Kate was in the past concurrently with Stuart even if they visited that same day on different days.
This all being said, Leopold couldn’t magically absorb into his former self. There would have been two of him, just like in Harry Potter when There were two Harrys and Hermiones running around. The Harry and hermione from the future had to avoid their past selves so they don't get all weirded out and attack themselves or something.
Leopold would have had to do the same thing. Chill out, step back, then when his other self ran away from the party, he would take his place.
