1) this is so far only a rumor ... from an anonymous e-mailer
2) even if it's true, there's no certainty that +Fellay will sign it
3) even if he signs it, one would have to read the terms of the agreement to be able to assess the full impact
So let's not jump the gun here. Several more steps. It could be sent back to Rome with suggestions for revisions, which Rome then may or may not make, and the whole thing could fizzle again.
In regards to #1, It's not really "anonymous". It is from an un-named source. Clearly, Matthew would not have posted an anonymous email without a well-founded reason to believe that the information contained therein is credible. He has not divulged the identity of the source, but this does not make it "anonymous".
Of course, you are absolutely correct about #2, though I doubt a serious proposal would have been sent to Menzingen without a well-founded belief on the part of the Vatican that the terms are acceptable to Bishop Fellay.
In regards to #3, try as I might, I cannot imagine terms that would be acceptable to Rome that would also be acceptable to a faithful Catholic. On this matter, however, it's probably better not to speculate because, as we've seen in the past, anything we can think, Modernist Rome can make even more despicable.