No, but if it were reliable info surely Canon would have said it to other places, not just to dpreview. Or put out a press release.
Instead we got a comment, possibly mis-remembered by someone at dpreview (and that's assuming that bunch of Canon haters isn't lying), that's utterly and completely unverified, but people seem to insist it's the gospel truth and will even go so far as to belittle those who don't believe it...as you did to sdz.
But even if a Canon rep did in fact say that the M6-II "replaces the M5 and M6" and did in fact know what he was talking about, all that that means is that they are discontinuing the M5 as well as the M6 (original). It does not mean they're not ever going to come out with an M5-II; it doesn't even mean that they don't already plan to do so.