i posted that is a rumor, and with rumors we never know if true or not until confirmed, and the insider that with this rumor also leaked the story about the world ends with you, what was true in the end...
You can assess that some rumors are more worthy of your attention than others based on prior leak credibility.
For example, the person that leaked TMNT and Enchantress for Injustice 2, that was too specific to be guesses so he had my attention for his next batch of leaks.
As for this person, I can't find a link to where he predicted TWEWY for the Nintendo direct. I know there were other rumors about a TWEWY sequel. Without seeing a link, I don't know if he adapted that rumor from someone else, or whatnot.
But I have seen comments like this: "Believing IndustryInsiderBro's shit that has changed multiple times since he started doing it, at that. Can we not bring the stupid over here?"
i know, with insiders it's always a bit critical, because at the end we have no proof until we hear a official statement ( in this case it would be d23). and maybe it's only a person who seeks attention, or maybe he know really the truth...at the end everyone can decide on his own if it's worth to talk about or believing it or if it's only bullshit...but for me i must say that Q3 2018 would be a good period of time to release the game...