So if Im following you, you're no longer saying that Mab hired Harry to flush out Maeve's plan, but rather that Maeve Lied to Summer to sick them on Harry's trail, long before Mab got involved? That seems like the sort of thing Mab should have noticed, when it became apparent that Summer was targeting him for no apparent reason but coincidentally only hours before she herself decided to hire him.
Im not giving up on it yet, but this seems to be unraveling a bit.
I was starting from the bad guys problem: The goal was to get the Archive, not (just) Marcone. The chosen method was to make it an Accords matter. Harry was the most likely to get the Archive as mediator. Problem was: Harry wouldn't have done anything if it was just Marcone on the line. They needed to motivate Harry to become involved.
Mab would have been motivated to become involved if
a) Maeve was involved (nothing good could come from it)
b) Thorned Namshiel was involved
c) it was somehow clearly a Nemesis-driven plot
d) she cared enough about her Accords to protect the new guy
e) she had an interest in Marcone because of Vadderung in one way or another
f) she had an interest in Marcone himself - maybe a bargain with him
...
b) is unlikely imo, because she had no idea who abducted Marcone. d) isn't strong enough in that instance, cause the Accords don't protect you from conflict, they just set down the rules for how it's got to be played. If Marcone can't protect himself or make sure he has allies - his problem. e) and or f) are quite possible, but we don't have enough facts to prove it. My WAG tried to address the possibility of a) because it is also an instance of c) as Maeve was Nemfected and her mother knew it, tried to persuade her to let herself be cured, Maeve didn't seem to like the idea... I thought it was logical that Mab wouldn't let her run around completely free, unsupervised and not under observation during that time.
Mab didn't know the details of what the Enemy really wanted to achieve. So she was likely to call in a favor from Harry in order to get some more information. But: Harry had the right to refuse if he didn't like it, and he could be expected to refuse to save Marcone. Getting Summer involved achieved that he was motivated to accept the offer. This would have served Mab's interests as well as the Enemy group (including Maeve if she was on board). So it's a coin toss as to who managed to do it in what manner. But I think Mab is the least likely, she can't tell a direct lie and she'd probably have preferred another way to motivate Harry. Summer trying to kill him did not improve the chances of him being successful.
Technically, Summer shouldn't have been able to attack Harry before he was officially Winter's Emissary. He had the right to refuse, so not even Mab's intention to recruit him as such was good enough. But I think the Queens can make mistakes if they truly believe something. The initial attacks might have been possible if Titania believed him to be the Emissary already (a lie fed by Maeve to one of Titania's spies maybe or something Nic orchestrated). Titania either had very bad information or very good information (knowing and reacting to a great danger to reality) or the initial attacks wouldn't have been possible.
So if Im following you, now you are suggesting that Mab was responsible for the attack at the train station rather than Maeve?
That's actually a fact iirc. She admitted to it in the hospital chapel.