Okay, let's get rid of Sinclair altogether, which would be one thing that would make the remake more its own entity while still having a connection to the original somewhat.
With Sinclair out of the picture, Sheridan would be the commanding officer of Babylon 5 from the very beginning. He would be the one who formed the friendship with Garibaldi back on Mars and chose him to be the new head of security.
He would have some issues with the Minbari after what happened to him in the Battle of Line. Which means his relationship with Delenn would have a rocky start. During the first season, he would start to be kinder to Delenn as he gets to know her but when he finally finds out what happened in the Battle of Line to lose his memory back then, he would become suspicious of Delenn's intentions, making him put some distance between him and her.