This is always brought up, but how do we know the noose doesn't protect itself? A two millennia old piece of rope that didn't snap as harry pulled on it in earnest and was farther unaffected by the cold lake water? just like the shroud of Turin, that thing shoulda fallen to threads. It didn't though.

The noose itself is definitely unnaturally resistant to destruction. I'm pretty sure there's even a WOJ about it, but the implicit text evidence is enough.

What it doesn't do, though, is heal the wearer absolutely immediately. Nic's wounds close when he gets shot, but it takes a distinguishable amount of time. Sufficiently violent overkill might not hurt the noose itself, but the strike only has to decapitate him and knock the noose loose.

What's more, it can presumably protect him from huge Holy Swords attempting to decapitate him.  If anything could cut the Noose that would be it, and removing the Neck should be a reasonable way to remove a necklace. The Knights certainly seem to favor decapitation as a goto tactic (for good reason).

Given how skilled he is at swordplay, it's possible that none of the Knights have ever managed to fully behead him in combat and see if it sticks. Cutting less than all the way through or too slow to knock the noose free before he starts healing isn't sufficient, and he's world-class at denying opponents the window for a clean strike. Massive explosives or an anti-tank round, on the other hand, do their damage in a few thousandths of a second.

As for armor, unless it's made from metal, it's probably hard to make a standard issue item that folks could universally refresh on their own.  Even though Harry is probably the Warden that visits Edinburgh the least, the others probably don't go as often as necessary to have someone do the refresh for them.

Well, better & more expensive materials can bring the required maintenance rate down considerably. The Council might not issue much gear directly, but it would be kinda stupid of them to tell their fighting force that resources to increase survivability are their own problem to fund out of their not exactly lavish paychecks.

As far as him throwing spells around: Nothing he could do offensively would come close to registering on the scale of that battle, where formations count in the tens of thousands, and are doing battle well out in front of the Gates.  So him throwing any sort of offensive evocations is pointless tactically, but would still both distract and fatigue him, when he already has a much more specific and  critical role, one that nobody else can do (unlike offensive magic that Fae would do better anyway).

From Harry's glimpse at the battle, did we actually see the Sidhe using magic against the Outsiders? A landscape composed mostly of bones would make for abundant shrapnel to throw around with anything that can push on it.

For that matter, air support doesn't even have to be magical. Find a grenade that still goes boom under Nevernever physics, buy lots, drop them from above.

The Laws of Magic have nothing to do with permission. Harry gave Molly permission to muck with his mind, and it was still a violation of the law.

I'm not at all sure I agree with that. The law is against "invading" someone's mind - that doesn't sound like a prohibition on mind magic done with consent. LtW's efforts to help heal the damage Peabody did to the younger personnel would fall under a similar situation. Also, for that matter, Molly and Harry's sparring sessions about trying to plant an idea in each other's head, which they apparently did a considerable amount of, would also be prohibited under the interpretation that consent doesn't negate the violation of the 'invade' law.

I have not read the story yet.
That being said, does it mention Hogs Hollow?  Is it possible that this trip to the West is when Eb discovered where he ends up settling down on his farm?

He doesn't appear directly. Luccio just alludes to him being the current Captain at the time and some of his warlock-hunting exploits.

Well Krakatoa was really big and is around the time Jim said Ebenezer first picked up the Blackstaff.   It's not impossible that the previous Blackstaff died during the event and that Ebenezer's first act upon picking up the Blackstaff (in desperation?) was causing the boom in a last ditch effort to stop whatever it was.

From reading about the actual disaster though, there were seismic warning signs ahead of the eruption. It wasn't extremely sudden.

And have Harry go even deeper in her debt?

If he wants a fae metal spear point for his staff, he'd probably end up owing a favour to the fae smith.

At this point, he's probably better off paying the svartalves in diamonds for any smithing he needs done.

I've started to connect the blackstaff with things falling to the planet(the classic 'calamity from the skies' trope like in FF7) but New Madrid was one that just didn't add up, being an earthquake.

Krakatoa was a big volcano, so really only Casaverde and Tunguska were "bomb it from orbit" type events.