The transitioning from Part 2 to Part 3 is the same, except Caesar survives and Joseph and him get married throughout the years. They adopted Holy, who soon got married and had a son by the name of Jotaro Kujo.
Of course, hint the ship Jotakak is in this fiction. Jotaro finds Kakyoin attempting to attack him on that regular school day, finding that he had a flesh bud on the very tip of his forehead.
If you watched all of Part 3, you should know what happens.
To understand this fiction, it is highly suggested you watch all of Part 2 and Part 3. During the fight with Dio, that's when the plot itself takes a turn. (You'll understand better when you read along the story, bare with me). Iggy comes in a little early, and yeah, minor things get changed around.
The only thing being changed during that duration is that Caesar lives, falls in love with Joseph, and marries him.
Updates are whenever I can and so far not planned, and I might not get to finish this story; it really depends on the popularity and motivation I've got.
See you till then!