... the Word of Kemmler ...
That one is a bit speculative; and the implications are... kind of huge, for Harry.
Per WoJ,
Jim himself was unclear if Harry was going to powerup in Changes with Mab, Lasciel, or a Darkhallow. This means Jim might have written any of them.
But since Jim wrote the powerup-via-Mab plotline, we don't know if Jim has decided that Lash is
gone-gone, or just changed/hiding/etc... but available.
Ostensibly, Lash (and all her knowledge) is
gone-gone. Harry no longer understands Ghoul, the Lash persona never comes, etc.
In theory, Lash's "speed-read" of the
Word of Kemmler is thus gone, too; as is the knowledge of how to summon Lasciel's Denarius.
But then again... Harry's an unreliable narrator, Jim lies, yadda yadda ...
The case for some or all of Lash (or her knowledge) being available is pretty easy to make; Jim just hasn't written the canonical truth, yet.
But if
Lash survived (aside from being a part of Bonnie)...
well.