Who else besides EarthScorpion and MJ12 is even all that knowledgeable and savvy about oWoD Mage and Sphere magic, procedures, and rotes?
It doesn't need oMage sphere knowledge. Not exceptionally - after all, if you've been following the quest, you have a passing knowledge of what can be done with most of the spheres up to level 2-ish. What it does require is a grasp of genre (yes, genre) and how to make changes by nudging rather than forcing people.
Seriously, one of the possibly-deliberate design features of oMage is that Mages want to avoid doing magic as much as possible.
However! Since we are Technocrats, we want to use magic as much as possible
as long as we understand how to keep things covert. And to do that, you have to understand genre and how to dress your effects up in it. And social engineering. That helps a lot too.
Hence, for example, "we mind control the guards to not be ready". That's a Bad Plan, because the guards want to be ready, there are lots of guards, and there are systems set up so if they aren't ready other people will try to make them ready. That's not what you want to do. What you want to do is set up things so they'll be distracted, and then use magic to reinforce the distraction. For example, with this sequence of events:
-> Henriette and Serafina together root a Correspondence ward in the limo. Combining that with the primium, the two of them are incredibly hard to locate.
-> Henriette, using Forces + Matter + Correspondence, sends drones to break exterior windows up on the higher floors and inject both her mini-drones and Serafina's modified insects which incorporate pre-loaded elements of programmable biology (sadly giving them a life expectancy of hours, but fuck them, they're insects)
-> Jamelia, now aware that other Union forces are attacking someone else (and so the locals will be getting increasingly worried), orders her subordinates to ramp up the paranoia of the person in charge, making them think that someone is attacking from the top levels, having infiltrated. This is a Mind + Entropy + Correspondence effect using the others as a focus, which reinforces the "someone is attacking from the top" paranoia which will lead them to take some of their forces away from the Security Floors and sweep these sectors to find the attackers.
-> Henriette uses her drones to systematically sabotage elements of the higher floors. She cuts power cables, severes phone lines, and generally makes a nuisance of herself, as if there's infiltrators on the top floors who broke in through the windows to get them to go after the attackers. If they choose
not to do that, or the spell fails, then Henriette continues being a pain. She's going to try to cut power to servers, for example, because if you cut the power to a server you can't wipe it. In addition, by cutting up the local security network she deprives the local Sysadmin of their Correspondence focus, which means they can't scry into an area of the building where she's cut all the camera lines.
-> Serafina uses Life + Mind + Prime + Correspondence to inflict "Terminator-gene" activation sequences into the HITMarks, activating their built-in anti-rogue protocols. However, this is actually a trap, because the REAL effect is the Mind effect built in which targets anyone who probes her attack (which is just a distraction designed to fail), designed to induce an emotion of paranoia into anyone who probes the spell (as clearly SOMEONE IS OUT TO GET THEM by using the Terminator sequences, even if they fail).
-> Serafina and Henriette watch for countermagic using Prime + Correspondence using the camera feeds set up outside and systems analysis, specifically seeking to locate the person who's locally in control. With both Henriette being annoying and the VAs being destructive, someone in charge is going to start throwing Primal Energy around and then they'll locate them.
-> When the location of the counter-magic hostile is located, it's passed to the VAs as an act of good faith. Decisions will be then made whether to attempt to blow them up or simply to support the other characters and let the VAs deal with them. By now, the sysadmin will either be a) deeply paranoid, b) low on willpower and/or quint, c) blind in several sectors because of Henriette taking out his foci, d) dead because he wasn't sitting somewhere safe and Henriette was able to shoot him with missiles, or e) some mix of the former.
And so on. From this, you can see that this sequence of events has several win states - either they're distracted and can't send everyone to the VAs, they refuse to be distracted in which case Henriette and Serafina wreck havoc on the top floors, they're paranoid and so make irrational decisions, and since it's all being done by Correspondence in a warded primium car, they're in relatively little danger. And everything they're doing is up top, thus making things safer for the attack team which is heading down.
(the only flaw is that Centurion is their BODYGUARD of HEROIC IMPERIAL BRAVERY protecting these WEAK WOMEN, even if one is a HALF ORIENTAL and VERY UNCOUTH, while the other is ITALIAN and thus UNTRUSTWORTHY)
That's what I meant about genre. The thing is, this quest?
Yeah, we're basically playing a spy technothriller. You should be playing as if you're controlling the protagonists of a technothriller. Of course, you need to take into account the difference in personal genres - for example, Henriette is starring in something which is basically Ghost in the Shell (and drones firing smart missiles are the best weapon when you're not allowed your mech), while Jamelia is in a more classical spy thing full of mindgames, and of course Kessler is every 80s action hero blended into one and the the messy slurry was used to paint a Terminator.
So devise a plan, and then use magic to nudge your plan into working. Magic is the tool, not the goal. Imagine yourself a spy technothriller plan, and then use magic to smooth over the "unrealistic" bits or make it work better. For example, "but what if they don't pay attention to the distraction?" "Don't worry, Mind + Entropy means we increase the odds that they send their backup squads to investigate the power cuts and the loss of cameras on the top floors. And if they don't pay attention to the distraction, then Henriette will keep on causing damage, and she can make one of these attacks a turn as her drones deploy microcutters to sever wires and cause short circuits and so on. So either way we win."
Mechanically, small effects are more reliable than bigger ones, coincidental is easier than vulgar, and mind controlling is a bad idea compared to nudging. Magic should be used to buff mundane circumstances, unless the magic is covert (such as Henriette shooting micromissiles at people from safety in a Technocratic base). In addition, your magic should always be rooted in a mundane skill, such as how Jamelia keeps on reinforcing these Mind + Entropy + Correspondence effects with Manipulation + Subterfuge, because if you can't root it in a skill you are throwing away free dice.
