faith and piety are, for the most part very different especially when you look at the original meaning.
"Pietas: "Dutifulness" More than religious piety; a respect for the natural order socially, politically, and religiously. Includes the ideas of patriotism and devotion to others. "
I always liked Piety as the 4th sword or "Gravitas"

Riddle me this, since it's late and I'm out of it, you COULD use a maneuver to place an aspect on the scene (for that is what this is, remember gm has final say of how the mechanics actually work in end) however, maneuvers can be removed by a roll that is higher then the maneuver or what you can do to protect the aspect. That being said a zone wide compel could cause everyone to loose their weapons (if they were metal yada yada), every one would get a fate point, then one guy could beat the roll, break the maneuver, and everyone could grab their guns as a complimentary action.
Net result, one guy is disarmed and wastes his turn, everyone else gets a minus one on their next action. So you CAN do it, but this method could be used to turn the tables back on the wizard. Just my two cents.

I have to disagree, Pietas, duty, strikes me as a big one, much in the same way hope and love are, duty, piety is a defining characteristics of a religion. To quote weird Al "I'm the pious guy the little Amlettes wanna be like"

In media res is a great attention grabber, the most important part is to still have 3 acts to your adventure, the start of the adventure is obviously on act two, the rising conflict. The most important thing to do is fill act 1, the build up, preferably before you finish the first action sequence. You can handle this in a few ways:
Font load background dump: You tell what they did before hand. "You've been chasing person X for hours, finally you corner him in a parking garage where you both jacked two cars, the race is on." ect. This method is quick and easy but might leave your players feeling like they have little control of their characters.

Rear end background dump: You finish the action then give all the information about how they got here in one large dialog, you can incorporate what they said and did during the action into your narrative.

Time rewind: they finish the action, are about to interrogate the baddy or fall into a worse situation then you pull it back to the start of adventure and let them play themselves into the conflict. This is similar to how the Odyssey is told.

Small tastes of background: write note cards with bits of background pertaining to certain players "Joan you're ticked at Nathan for letting the warlock slip through your trap at the baseball field." "Frank, you lost your gun during the struggle with the demon he summoned." Give them to your players if they bring up a complimentary point or you want some more conversation rolling. The players "feed" each other background as you continue the action.

Leading question backdrop: My personal favorite method for this type of gaming, ask your players details about the background that keeps your narrative mostly unchanged. "Joan who's fault was it your trap for the warlock failed?"  "Frank, your gun is gone, how the hell did that happen?"
Maybe Frank's player suggests the demon on his own... suddenly its no longer a two man race you add in the warlocks demon coming up from the rear.... you get your players to play their characters, keep your story, and maybe add awesome things your players come up with you never thought of.

For the most part intent should be considered for the supernatural power at least (the council might think otherwise). You make a ward that no reasonable person should be able to kill themselves on and someone does, you don't become a "law breaker".

A spell tossed at the ward is the spell that comes back, the intent is squarely on the caster not the maker of the ward, you reap what you sow, I go as far to say bullets and weapons rebounding are the fault of the user more then anything. If you throw a baseball at a rubber wall and it bounces back to hit you who's at fault? But, if you add a bit of top spin to your wards all damage is on your head.

In YS, there are four different skills that are given as defenses against intimidation (deceit, presence, rapport, discipline), meaning that just about any social ability at all is a defense against it, and all magic users have a built in defense against it.

For the most part all four "can be used" but depending on the threat I'd rule only certain one are available in that situation (or if the person rolling can make a good reason).
For example, you're tied up with a guy yelling at you "Tell me where the girl is or you get it" rapport and presence might not cut it for defense. Your ability to be sociable might not cut it as a means of 'deflecting' the fear your assailant is putting out.

I'm not too sure about the Topping off by a wizard, remember Harry's rings held back a bit of kinetic energy each time he moved his arms and once he did a half an hour of heavy bag to grab a charge back instead of just looking at it all cross eyed saying strange words. This strikes me that you can make an item that can be recharge by alt. methods, Elaine, if I'm remembering right, said one of her items could be charged from a wall outlet. Maybe you need to toss a ring in a fire for a bit so you can let a jet of flame out again, the possibilities are varied.