You mean Spark of the Rebellion? I did not know that, or I'd forgotten. According to https://starwars.fandom.com/wiki/Star_Wars_Rebels:_Spark_of_Rebellion: The movie re-aired on the ABC Network on October 26, with a new prologue featuring Darth Vader and the Grand Inquisitor.
Yep. I've never seen it without the Vader prologue. In fact, it was the only episode of the show that I saw for a couple years because I didn't have access to cable TV at that point.
Some episodes were re-run on the regular Disney channel sporadically. I recall seeing at least one season two episode there.
I have a vague recollection of the first season being released on some kind of Disney stream app or site (pre Disney+, obviously) at the same time as it was broadcast. No clue if that was free, or required a premium cable subscription too.
Disney XD maybe? That channel had more teen-adult programming than the others. I honestly don’t remember. I didn’t start watching until I got Disney+
Each aired on Disney Channel a while after they aired on XD. I watched everything up to the last season that way because I never had Disney XD. I don't remember exactly how long the Disney Channel airing was after the XD one, but I do remember that I was always a handful of episodes behind everyone watching on it on XD.
I think it was on at weird times and moved around a lot. I remember I kept having to search for it, because it could never seemed be on at the same time with any consistency.