Scientists, once taken, often have access to lab equipment. If we get scientists during the uptime, we could possibly even use them to get equipment from their labs on the following downtime, right? Especially if the rolls go really well. I'm glad we're doing this.
Psysquid knows that this isn't exactly what Chemista needs. He even said so in how he presented the mission - it's not because of Chemista. Instead, we can control how this works out to turn it into what we want.... which is exactly what we are all about, and something that Psysquid should be especially well suited to helping turn out as we wish
Take the scientists. Control them. Do not, at first, change their bodies (their minds are free game, and should be changed).
Interview the scientists. With both Chemista and Psysquid present and assisting. We want to know what equipment they have access to, how access to it is controlled, and then we can decide from how they talked and what they said if we want to mutate them at all, before, or after a run is made to get what we want to take.... or even during the run, if that seems exactly perfect.
As far as the kidnapping run goes, I say Psysquid, mostly because it is his 'turn', as well as that he should be pretty good at this sort of task (because of intelligence) and because he foresaw many parts of the mission which will surely give him even more bonuses. With him send both succubi and the remaining complement of supportive cog minions, just in case, but also because that's what we do, and he needs a chance to possibly lose some more of them, or not.
Before we send him out, have a chat with him, remind him that the best way to be bad is to be really good... at what we ask him to do. But that might not get him immediately punished, and we do want him happy. Is he happy enough? Would installing anasquid's tank in his quarters, and requiring that he keep the beast company, take it for occasional walks around his room and swims around a lagoon and such, make him happier? If that seems to be something that entertains him, then make it so. If that's clearly not an answer he hoped to hear, offer a lesson where we scold him as a warning to ensure that he continues to give his loyal best towards achieving our evil aims, with threats of being made to do such things as becoming our anasquid walker because he's just not good enough anymore to do the things we really want done as the main topic.