You know Star Wars (and movies in general), they can always come up with some bullshit reason to cover a plot-hole. Like, how Darth Maul somehow survived tho cut into two pieces, and managed to make his way back into official canon (thru Rebels) as being still alive right thru to near the time of A New Hope (as Rebels reaches that era).
As much as I like creative writing, let's be honest here. Maul surviving that and returning in Rebels is crap. He was sliced in half and fell down a (seemingly) never ending pit. Ridiculous really, what next - Han survived too? Even with the planet blowing up, who knows?
I've liked Rebels from what I've seen in bits and pieces, but it's lost a lot of credibility IMO by having Maul survive and return.