I highly doubt that anything short of the Mothers could stop a Nemfected Mab.

Murphy stopped Maeve with a handgun.

Mab's already told us when she is going to die. She's bound by fae rules. She cannot tell a lie.

"I am Mab. The stars will rain from the sky before Mab fulfills not her word."

The last book in the BAT is called Empty Night.

Molly is the Winter Lady, not the Lady of Chicago. She's based out of Arctis Tor (or Arctis Minora). She barely uses her apartment. When she's in Chicago she's a tourist. Plus, Mab keeps her moving. And that's intentional.

My guess would be Harry, Marcone, Butters, and Mort.

The unknown magic was Ash, Mouse's 'My Shadow'. Cowl calls My Shadow by that name several times.

I finally figured out what bothers me about the fae queen mantle wearers. At least for Sarissa and Molly, the other queens we don't know how they came to bear the mantles. Maybe they volunteered, maybe they didn't.

But Molly and Sarissa are slaves.

A slave cannot choose their own destiny. They are not free to leave at any time of their own free will. And before you get on about Butcher's past choices limiting your current choices, let's apply that to slave-held people in the past. Did their decision to draw water from a certain river lead to them being captured and sold on to slaveholding people?

They may be given power, but they're still in a gilded cage. Worse, since they're immortal, it's an eternal cage. They can't even easily escape it in death.

Normal hunting loads are copper jacketed lead. Shotgun slugs or shot are lead. Although they do make steel shot for hunting waterfowl. Military loads sometimes have iron or steel penetrators.

A hollowpoint cavity could have a steel or silver bead dropped into it and epoxied into place making them deadly to weres or fae.

Sorry if this rambles a bit.

I've been pondering Battle Ground and Peace Talks.

When Molly launches into the explanation of why she can't step outside the circle in PT, it's also a clue for later on. Her mantle is more invasive than Harry's. Shedding her mantle the wrong way would damage her. And Harry's can inflict pain if he goes against Mab's word. Which probably means that Molly can't go against Mab's word. But as we see in The Good People, she can do as she pleases provided she doesn't.

She has some free will, but nowhere near what she had as a mortal. But, there's no way Uriel would stand for a total loss of free will or the loss of an immortal soul. So, we can assume that she's still mortal, but under a geas and a glamor. Jim has said that the mantle is changing the bearer's DNA, but that could be explained by Molly and Sarissa looking like twins now.

So, she's got to behave as a fae would, equalizing scales, hoarding knowledge, vulnerable to iron.

She also appears more fae when she's leaning into the mantle, like when she was coordinating communication for the fae and addressed Harry as Mab would, with eyes and ears totally fae. Was that because her mortal mind was occupied and left the mantle to answer Harry? Because, coming from a tripartite entity like Hecate, you have to assume three or all six queens have some sort of hive mind, at some level.

The final point I want to bring up is during the limo ride to the Carpenter's house, Molly leans into Harry's hand and tells him, "You're my knight too, Harry." I don't think that was the Winter Lady speaking. She made sure that they were isolated with no outside observers. And the Winter Lady has never given the knight an order. In fact, everything we've seen about Winter Law argues against it. Winter Law is whatever Mab says it is. Never Molly, Maeve or even Mother.

I offer a WAG:
In this quote, Mab isn't saying "I will never lie."
She is saying, "I'm not lying... yet.  But I will... after the Stars fall from the sky."

I'll go you one better. We know WHEN Mab will lie. The last book is called Empty Night. A sky without stars.

He bound her as a fae is bound by equal exchange.

Just like he later bound all of the supernatural nations present under guest rite.

It's a different type since it required no battle of wills, but it's just as binding, within its limitations. We've never seen what happens to a fae that fails to fulfill a contract, but as we've seen with Harry in PT, there's a real, physical consequence. Molly described a unfulfilled contract owed her as an itch that she can't scratch.