The article also indicates that Alex Navarro (apparently from Harmonix, the game’s publisher) said he can’t comment on the multi-mic support. I think that sounds like good news.
The last paragraph of the article is a bit silly:
There have also been speculations related to the use of the fresh, remastered versions of The Beatles tracks, which will arrive on sales via the One package. It would make sense to use the higher quality tracks for the game but nothing is clear at the moment.
From what I understand, these games always use the original master tracks, so using the remasters isn’t really relevant. I wish I could find a link about that.