The whole EU is pretty much considered non-canon now but this seems like a special case considering Son of Dathomir was released AFTER the EU was declared non-canon, not to mention that it's based on storyboards of unfinished episodes of The Clone Wars. I haven't read it myself yet but I wonder if it could have any effect on Darth Maul appearing in the New Trilogy or Rebels.
Yes. There's no way Maul will be in Rebels or the New trilogy, but those are not the only two options for him. He'll probably be in one of the spin-offs with Obi-Wan. Basically an expanded canonical version of Old Wounds.
Son of Dathomir might have given Maul a decent reason to be in Rebels. If Sabine's mom was actually Rook Kast, then the show has a direct connection to the Mauldalorians. So while it may not be likely for Maul to be in Rebels, it's definitely not impossible.
Finally got a chance to read the whole thing...Excellent read. I'd say Maul is pretty much guaranteed to appear somewhere down the line. He SURVIVED. I didn't think he was gonna but I'm so glad...Hope we get to see more of him soon.
i know Maul is an alien, but no way does he survive that. It is ridiculous. But i can see Disney wanting him around as the occasional villain.
SoD is absolutely canon - its CW in another form, and LFL confirmed it. Same goes for the upcoming Ventress novel, and the Utapau story reels.