Jim just got married in October.  Yes, it's his second marriage, but it's still a big change.  Plus, add in what has been speculated about the TV show.  Even before this I guessed (and posted) that PT won't be completed until sometime between the end of this year and early Spring 2019.  That's my prediction and I'm sticking to it.   

Nearly everyone who has told Harry anything about either the Starborn business in general or his mother specifically has either been:

A. Evil and trying to turn him to their side;
B. Evil and trying to kill him; or
C. One of the above and now dead.

Suffice to say, Harry doesn't have a lot of resources he can go to for information about either of those -- not without incurring a huge cost for that knowledge, anyway.

I also agree that he's probably in a lot of denial, about his mother specifically -- like any child, he wants to believe his mother was Good and Right (hence him defending her when Luccio speaks of her) and, as above, three of the people who've said the most about to him about his mother are a literal demon from Hell, the man who murdered her, and the man who started the Black Plague as a second honeymoon. Of the rest, two of them have stated that the White Council had a kill order out on her as a Warlock.

The only person who seemed just simply friendly with her and was not evil was the Gatekeeper, and getting information out of him is ... tricky.

So yeah -- Harry has every reason to fear that any further information he gets about his mother will paint her badly, so he's probably reluctant to seek it out.

Good post with very solid points, but you're missing something.  (Read below)

   Knowledge was also deliberately kept from him.   His mother died when he was born, his father, when he was six, instead of stepping forward and claiming him, his maternal grandfather let him be dumped in an orphanage for the next four years with no clue of anything except vague memories of his loving father in the old station wagon they traveled the country in.  When he was adopted by Justin he had no reason to believe he had any living family.  What little he knew of his mother is what he was told by his adoptive father, whom he loved and trusted until he was sixteen.  Then the crap hit the fan, his fae god mother didn't or couldn't tell him the truth... When he was saved at the trial by Eb, he basically learned nothing about his mother other than she was a killer rebel who was under sentence of death.   Eb then took him in for the next three years, never even hinting that he was really his grandfather... Later in Blood Rite when a wounded Harry confronts him about a lot of things, Eb still couldn't or wouldn't tell him the whole truth about who he was or his mother..

I liked your whole post, but I want to point something out.  Eb didn't tell Harry very much about his father either.  In Blood Rites Eb finally confirmed what Chauncey had told Harry in book 2 about his mother's death, but not about his father death.  He only said something about his father having "as good a soul as I have ever gazed."  (I'll have to look up the exact quote, I know my wording isn't 100% correct.)  Anyway, this implied Ebenezer shared a soul gaze with Malcolm Dresden but little else.

Ebenezer is the one person Harry can talk to; when the opportunity arises, without incurring a debt.  I could buy that Harry was so inflamed when he heard that Lord Raith murdered his mother that he couldn't think straight.  However, I think the time is past due for Harry to want to probe Eb for more information about his father.  Harry really hasn't had many opportunities to do this in the past.  I'm hoping there will be an opportunity for that to happen in Peace Talks.

Snark Knight do you know where that interview is about some apparent continuity errors being hints of a deeper clue? I would love to see that. It certainly would be a neat way to fix a few problems.

I agree, I haven't heard Jim say that in any interviews or Q&A's, though to be honest I haven't watched many of the YouTube videos that feature Jim this year.  The ones I have watched have had very little new information in them so I haven't felt compelled to keep up.

Thomas as new Lord Raith figurehead for Lara.
Murphy meeting her dad.

I like the one I highlighted, the second one not so much.  However, I could see a future scene; not necessarily in Peace Talks, where a supernatural character meeting Murphy for the first time says, "I saw your father in action once.  He was dissuading a friend of mine from preying upon another mortal.  Your father was very effective.  He annoyed me very much."  Something to both add some mystery and get Murphy thinking about her dad.

However, my prediction is we will be shown that the White Council has lost its internal unity.  It is only pretending to be unified to the outside supernatural world.  The division we saw in Changes haven't healed.   Cristos has more influence and the Merlin is accommodating him in an attempt to show unity to both real and potential outside threats and protect the Council from the internal threat of dissolution and civil war. 

This will set up a long term problem for Harry, and one that goes well past Peace Talks.  Harry will have to decide where he stands, and probably on more than one issue.  For example, I could see Harry initially decide to support the Merlin in Peace Talks, much to Arthur Langtry's surprise, only to decide to split with the Council at a later time under different circumstances.   
 

I'm still wondering what exactly is taking Jim this long to finish Peace Talks.  On Reddit Serack mentioned that he told his beta readers about some problem.  But Serack didn't say what it was.  I opined that it might be some mental health issue like maybe depression or something, just something that in some way affects his brain/mind.  Serack shot it down in saying it "wasn't his head".   I'd say though it seems whatever it is, it has affected Jim's ability to crank out books like he use to.

I don't expect Jim to be finished until at least the end of this year and I won't be surprised if it takes a number of months longer than that.  In one of the YouTube videos featuring Jim that was put out early this Summer, he told his audience he was only half way done with Peace Talks, but added that in a few weeks his personal situation; his new home and writing set up (and I think his life in general), would finally be in a place where he could concentrate on his writing and hopefully finish PT by the end of September. 

On the general theory about the best laid plans of mice and men never quite working out the way they were intended to do so, I guessed Jim getting everything the way he wanted it to be would take longer than he estimated and I always thought his estimate of how little time he needed to finish Peace Talks (half the novel in a little less than four months) to be somewhat over optimistic.  So I'm guessing PT will be finished sometime between Jan. 1 and June 30 of next year. 

I sure do miss the tweets Jim made when he was writing Ghost Story where would update what where he was by the percentage of his estimated word count.  "I fired up my laptop and I'm at 75% of my estimated word count."  Of course Jim went over his estimated word count, but those tweets really showed us the progress he was making.  It made me feel I was less in the dark about Jim's writing process, and for me, helped build my enthusiasm for the release of that book.  (Of course, Jim also tweeted about things that had nothing to do with his writing and occasionally responded to other tweeters, and doing so must have taken time away from his writing, so I understand why he's cut out a lot of the social media stuff, but I wish there was some middle ground where we could be a little more informed.)   

I'm certain we will hear when the book is finished from Jim before Amazon knows when it will be released.  Even if Amazon puts out a release date the day Jim announces he has finished Peace Talks I won't believe it because there is still some remaining editing even after all the pre-finishing editing Jim does with the input he receives from his Beta readers.  Only after that occurs can the publisher give Amazon and other booksellers a reliable release date.

There's probably also a matter of practicality -- this story's set before the Wardens had a standardized way of non-magically killing folks (Luccio's swords), so the interpretation might have been less strict for Wardens specifically, in acknowledgement of the difficulty of subduing warlocks without using magic.

The Law against killing a human being with magic isn't based on using the proper procedure to fulfill a set of written legal requirements, such as; reading a suspect their legal rights by mortal police in the U.S. is required by a specific Supreme Court ruling made in 1966.  It's based on the idea that killing with magic twists the psyche of the person who does it.  It sets them on the path to becoming a warlock.  We saw this in Harry.  Harry killed Justin in self defense and that came close to pushing him over the edge.  So I find it difficult to believe the White Council only learned this a century and a half ago.  They would have devised methods to avoid burning someone to death with magic.  So there must be some other explanation.

Luccio says the she "seen no evidence of magical defenses" in the four warlocks she spotted, and further states "an overwhelming attack might take them all at once."  She does not say "kill them at once," though her language can certainly be interpreted that way.  So perhaps she meant she could; very painfully, incapacitate them all at once, and then either arrest her suspect or if necessary kill him with her sword.  I think it is either this explanation or Jim forgot the specifics of the law against killing with magic.  So if it is the former I think Jim could have written it more clearly.  Then again, there might be a third explanation.

In the introduction to the story Jim said he wanted to focus on the young hotheads of a given era in the Dresdenverse verse.  So young Anastasia Luccio must fall into that category.  Unless Jim gives us information to the contrary, that still puts her a long way from Harry's thinking in Storm Front when he was considering burning down the shadowman's home and everyone inside it.  Luccio's thinking was more analytical, more dispassionate.  So, we could take the extreme position that this is a clue that Anastasia is really a much darker character than we realize.  Perhaps she is a member of Harry's Black Council.  She wasn't Peabody's victim, she was his collaborator and the plan all along was to set up Morgan for La Fortier's death  The mental damage the Gatekeeper detected in Luccio she did to herself.  It could have been done by accident in order to convince Morgan that someone else was manipulating her or Luccio might have realized that she might need an explanation or alibi should things go wrong, so she decided to let Peabody use some magic on her to better help the illusion her relationship with Harry was based on her real feelings and desires, and provide her with an alibi should she need one.  I'm not saying I buy this WAG myself, but it's more satisfying then saying Jim's use of language was sloppy.