Proven Guilty final iteration.

[g33k]

I'm pretty sure Mab had Molly brought there...

Yeah, this looks like Mab's doing to me, too.

I'm unclear if Mab stepped in on something Maeve was doing with Molly; having the Fetch kidnap Molly may have been rescuing her from Maeve!
 

[morriswalters]

Maeve was a tool of the Black Council and the Adversary.  Harry is the threat and Molly was meant to be the cure.  Her use of Black Magic and Michael's friendship would have put Harry in the position of going up against the Senior Council when his allies were engaged, and the Merlin would have ended him.  It would also have deprived Mab of her Knight.  As it was he got the time to do the political thing and Michael was able to get Harry's allies through to the trial.

[g33k]

Mostly, I agree with everything you said.

But I've minor questions about this bit: 

Maeve was a tool of the Black Council and the Adversary ...

It isn't clear to me who / what "the Adversary" is.

It's an old name for Satan, so... maybe him?

Nemesis, as an agent / agency of the Outsiders?

Another, as-yet-unidentified party?

Alt-Harry, Time-Traveling and Mirror'Verse and Seven-fold Lawbreaker (yeah, I know, Time is one of the seven), and more?

Similarly for "the Black Council" -- are they a tool of the Adversary?  A full partner, or a "junior" one, or just allies-of-the-moment?  Just an alternate view of the same thing(s)?
 
Maeve was "infected" by the corruptive "Nemesis," we know; and we believe it to be something Outsider in nature (though AFAIK it could be just allying with Outsiders at some moments, and have its own agenda).

In fact... there's enough questions here, IMHO, to warrant its own thread.

So mote it be...
 

[g33k]

Earlier, I wrote: 

... I'm unclear if Mab stepped in on something Maeve was doing with Molly; having the Fetch kidnap Molly may have been rescuing her from Maeve!

And now I've realized what was niggling at me:  Scarecrow.  Still unclear about Maeve, but... bear with me:

Up until Harry escaped from "Darby," he was massively overpowering the phobophages.  In the hallway, in the movie-screening... It was Harry Dresden KICKING ASS (yes, some Lasciel-rage, some hellfire... but Harry laying some serious hurt on the 'phages (more or less as we expect Harry to do when innocents are at stake)).

As of Scarecrow... notsomuch.

And that's when it was the Fetches, instead of whatever schmuck phobophage Maeve-or-whoever was scaring up (heh) from the dregs of the Nevernever.  We don't really even know if they were faeries, I think -- did we ever see Iron used against them?

N.B. I'm not certain it WAS Maeve; but I suspect her above any others, at present.  But whoever -- they didn't have Fetches.

Fetches belong to Mab!

That was the point at which we know Mab was taking a personal interest in things; actually giving orders and making stuff happen, not just wait-and-seeing. And what did the Fetches do?  Why... they brought Molly straight to Mab, in the heart of Winter, where Mab could personally oversee everything else.  Not what Maeve would have done, or wanted done; they were NOT Maeve's instruments!
 
I'm not sure who was running the first part of the operation... inviting Darby Crane to the SplatterCon!, making sure Molly and her drug-addicted friends were there, etc.  (I do see, btw, the temptation to make Sandra Marling more than a muggle rando-horror-fan with minor flair for organization; but she could just as easily be someone else's catspaw.)  Madrigal swore under oath that the phages, at least, were nothing he expected or knew would be involved (and I see no reason to suspect a lie); so those elements could have been Maeve, or a subtle pre-arrange by Mab to lure her enemies into the open, or... well, lots of options, really.

But as of Scarecrow -- Mab.

And if Harry was right -- that Scarecrow killed Glau first because he was the cutoff to  Darby's controller -- it strongly implies Glau was Mab's agent, and Darby was also there by Mab's will.

Which in turn strongly implies that the entire operation, start to finish, was Mab's.  ONE of her objectives was to unearth some hidden foes.  ONE of them was to protect (and cultivate) her next Knight.  I suspect she had an eye on Molly as an asset (possibly as backup Lady even then -- the Lea/Harry/Molly throughline is clear).  She got to ID a Denarian (and maybe others; e.g. BlackCouncil wizards), and show Harry the involvement of the Fallen, with Harry then fingering the Denarian for Nicodemus/Anduriel.

Deep, subtle play.

Mab.
 

[morriswalters]

You see the Scarecrow exactly twice.  At the Fool Moon Garage and at Arctis Tor.  Molly mention's him earlier in a foreshadowing.  There are five attacks by the phages. Three where someone dies and two where they don't.  At the second attack in the screening room someone uses a ward on Dresden and produces a murk.  You've seen the ward before in Summer Knight, Maeve uses it on Slate. And you see the murk in Small Favor produced by Mab.  Mab wouldn't have needed to ward Harry, she could have used him as a sock puppet, as she does at the beginning of Summer Knight. This was Maeve's, as is the last attack, which was the only attack originally planned.  I infer this since the lights were sabotaged.  The second attack was a panic attack after Harry Showed up, this attacked served some other purpose. I think to kill off the middle man at the Con.

[Kindler]

Potential counterpoint: the lights went out in the hotel during a confrontation in which a significantly-powered Ward was thrown up. It's possibly the result of mortal magic use.

[morriswalters]

The spell cast at the Shedd Aquarium never so much as made the lights blink.  But that is neither here nor there.  If you posit that the fetches were just showing up at random, OK. But it would have seemed that Harry knew better than to blow the lights during a terror attack.

[g33k]

You see the Scarecrow exactly twice.  At the Fool Moon Garage and at Arctis Tor.  Molly mention's him earlier in a foreshadowing...

Also, Daniel attests to Scarecrow as one of the Molly-abductors, but that probably counts as "the same" incident as Arctis Tor, since Scarecrow's still in possession of Molly at that later point.

... There are five attacks by the phages. Three where someone dies and two where they don't. 

First was Pell, beaten by Hammerhands.  I think this was Mab, an incident carefully designed to draw Harry into the plot.  As such, likely a Fetch.

Then the Reaper in the Screening Room, where it both killed & injured people.  This is where Harry met "a kind of ward," and the myrk; it also got frosty, so likely Winter.

I don't think any of the Queens were behind the ward:  it was too weak, and Harry was able to "chop through it" with his will (n.b. not even a counterspell!), and even "get a sense of the spell" (the binding that Maeve laid upon Slate was, I think, just mantle-stuff: Winter Lady binding Winter Knight).  There was no hint of anything but generic "black magic" here, and my bet is on a middling-power mortal lackey for this.

Is the "murk" in PG the same (or at least the same sort of thing; a related thing) as the "myrk" in SF?  I'm willing to say a solid "maybe."     In PG, it dragged at him a bit, and actually "congealed" to almost stop him at the door; but Harry's pentacle is able to largely clear it from the screening room.  But he could barely clear his own armslength in SF.

And the Reaper was taken out in a single shot.  A normal shot, no Hellfire boost.  I don't think it could have been a Fetch.  Even the little ones in the theater, guarding the Way (to Arctis Tor) were resistant-enough to magic that no single shot of Harry's could take one out.  This says not-Mab, to me.

I dunno, maybe all the phobophages were Fetches.  Harry eventually pegs them that way, because "phobophage + mirror-access = Fetch" (so far as he knows), but we don't actually know that he's right (unreliable narrator), nor that mirrors were always the relevant entry-point.
 

[morriswalters]

No, I missed it, the Scarecrow was at the Carpenters.  So three times.

Myrk or murk, I don't see anything more then Butcher changing the spelling for effect.  Mab was behind the Myrk in SF and it had to be thick for the Hobs to be there.  In the screening room it just had to be dark enough to frighten the audience.  There are no other players. It was either Mab or Maeve.  The only unknown in the book is Sandra Marling and she has a cell phone. Unless you think Glau was the summoner.

They actually see Hammerhands and the Reaper in the battle in the courtyard at Arctis Tor. So yeah I think they were fetches.