WB DT, regarding the DFS question you presented.  On the surface of it, the elimination of the word "Definitive" from the Feasibility Study might seem like a very big deal, but I believe it is just a matter of semantics.  After all "The" Feasibility Study is, in fact, definitive and the PFS is, in fact, "Preliminary".  By referring to it as just "Feasibility Study" and without any qualifying article I think it just emphasizes that this upcoming "Feasibility Study" is the final Feasibility Study and that there is no need for further qualification of the term.

Of course, those are just my thoughts on the subject and may not have any bearing on the reality of the situation, but in my view the management eliminated any adjective to the term, Feasibility Study, as a backhanded way of actually emphasizing that this is the Real Deal and that no further Feasibility Studies would be coming after this next one.

As for your other notation about the mile post being somewhat blurred, that has been the Modus Operandi of LAC for years now... nothing new about that.  They never explain why.  It just cements the concept that published Calendar Events by LAC are subject to "Alternative Truth".  In the matter of published Calendar milestone events and the frequent moving of the Goal Post by LAC management, it always reminds me of the quote from Spiro Agnew:

"I apologize for lying to you. I promise I won't deceive you except in matters of this sort."