Yeah, that's generally my interpretation. "Hide this device in Rolfball's tank" or "At the end of your shift, turn off the shield-generator." That kind of thing. The coercive power of go agro is generally limited to being in someone's presence because its very trigger is predicated on doing immediate, one-sided violence to them. In-brain puppet strings has a much less immediate, much longer-term coercive effect.

I don't think it's necessarily an issue of "being a Grinch" but rather one of what the interplay of mechanical and fictional effects might be. Not all groups of people are "gangs."

For instance, in the case of a Hardholder or a Chopper, you have a group of people who are dedicated to doing violence at your behest or on your behalf. But in the case of a Hocus, you have a group of people following you because of their beliefs, but who may have no interest in doing violence on your behalf. Your followers are expressly not a gang (unless you whip them up to it through the use of frenzy, which has its own risks and consequences).

So no, a rag-tag caravan of people following a Savvyhead around is not a gang. It's a motley group of people who figure you're their best ticket out of whatever misery they were in before. But the moment you tell them, "OK, I need you all to go over there and kill those guys," (i.e. use them like a weapon) they're likely to balk. Why? Because they're not a gang. They're just people, and in all likelihood people who don't want any trouble. Not everyone who lives in a hold is part of the Hardholder's gang. In fact the gang is usually a pretty small minority of a hold's population.

My advice is therefore a bit different from ColdLogic's, which is that you should make a distinction between "people who follow your lead" and "people willing to do violence for you," and that you should generally reserve the latter for people who felt that it was important enough to spend an advance on. The fiction is king, obviously, but it's important to keep the underlying game mechanics in mind in that fictional context.

Looks like a good mix, with lots of tension just under the surface and ready to explode.

Yeah, that makes sense. FWIW, I'm a "bloody fingerprints" kind of a guy when it comes to a 7-9 on act under fire; Yes, you'll get what you needed, but with consequences that you probably didn't want. I'm also a fan of occasionally putting failure to achieve your goal as one half of the "ugly choice," as it's interesting to drop a big ol' "OK, but what's it really worth to you to accomplish this?" in front of the players and see what they do.

Ebok, I think it boils down to the fact that I'm not a fan of making 0-Harm attacks. It feels like a lame way to bring Hard into the equation, which seems kind of cheap considering that Hard is literally a measure of how willing you are to inflict bodily harm to get what you want. If you're not inflicting any Harm - indeed have no intention of inflicting Harm - then that's doesn't really read as "Hard" to me, which takes the Hard-based moves more or less off the table.

That said, I do agree with Ebok whole-heartedly in that I think the issue is one of what's at stake. I also think that's where clearly determining the PC's intent should happen as well.

And yes, part of the issue is "what happens after," right? OK, so what if you can stop Dremmer from going through the door? Does that give the quarry time to get away? Or does it just kick the can down the road a minute or two and Dremmer is still in a homicidal fury?

If delaying Dremmer by grappling - with the intention of not hurting him - gives the quarry time to get away, then sure, this seems like a good fit for act under fire. 10+ you do it, by the time Dremmer breaks free the quarry has vanished. 7-9, you get the standard worse outcome (you slow Dremmer down a little bit, but he slips out or your grasp quickly enough that the chase is still on, though in another location and certainly under different circumstances), hard bargain (Yeah, you manage to restrain Dremmer long enough for the quarry to make a clean get-away, but he fucking bites you in the process - have some Harm, chuckle-head), or ugly choice (You can stop Dremmer long enough for the quarry to make a clean get-away, but you'll actually have to inflict Harm on him to do so - do you want to? Also, hope you're not merciless; oh shit, you are). 6-, you probably get popped/bitten/thrown and Dremmer gets his hands on the quarry while you're still seeing stars.

But if there's no where for the quarry to go, what you're actually talking about isn't slowing Dremmer down, but changing his mind, and that's a whole different kettle of fish. As I see it, your options are to a) throw Dremmer a serious enough beat-down that he re-thinks his position (and whether or not he's willing to fight you back determines whether this is go aggro or sieze by force) or b) convince him that there is a better time/place/method/opportunity to handle whatever his beef with the quarry may be, which is classic manipulation. This might be a tough sell, and as the MC I'd be pretty fucking specific about having the PC establish just what leverage he or she might have over ol' Dremmer. You might be robbing Peter to pay Paul, and I'd probably pretty brutal about what constitutes the "concrete assurance" required to get Dremmer to stand down if the PC managed only a 7-9.

perhaps an adaptation of the Child Thing?

I feel you, but given the short-term nature of your parameters, you need something around which to focus. Also, don't think of it as "the plot," because it's not. You're using the stuff you all brainstormed at the beginning, you're just advancing some part of that to the forefront in terms of the Threat you're posing to the players.

There will absolutely be stuff that ends up on the cutting-room floor, but that's true of every good story. Don't sweat it, and better yet, sock some of those cool tidbits away for later (re)use.