When ABC News was relaunched after the debacle that was The National, they decided not to revive Majestic Fanfare and instead opted for a more contemporary theme for their TV news bulletins. That was over 30 years ago.
Maybe there's a slim chance for a contemporary update to the ABC News theme used on TV circa 1986-2005, but I think the chances of ABC News on TV using Majestic Fanfare on TV in 2017 are approximately the same as those of Ten Eyewitness News using their old "Move Closer To Your World" news theme from the 1980s ever again: 0%.
As I've said before, my personal preference is for either a remix of their current TV news theme or a completely new composition and I'd even be willing to predict that the ABC will most likely pick either one of those two options.
Re, the ABC's logo: I honestly wouldn't surprised if the "classic" logo does eventually become the corporate logo again if they plan to use it for ABC News. Aside from ABC2, the metallic pretzel from the Early 2000s isn't really used much on TV anymore so it probably wouldn't be an overly radical change.