For the moment it seems that Wile and Mirage are both locks in for this quest, both for mechanical and character reasons (giving poor Mirage more screen time is always nice) so the question is who to fill the last slot.
Monogram like many said is busy with other things and wouldn't quite fit in this merry band we are making (he kind of is the poor man's Russ for the moment), Technor is shackled to his actual job off psychoanalysis for the foreseeable future, Dennis is a bit too unreliable for how big this job is and while Janna would be a nice boost to any occult part of this quest (and considering where the murder took place there is a real chance of it mattering) she probably will be more useful doing other stuff (Felldrake's quest or other stuff depending of how her interlude goes).
That leaves us with either Ludivine or Max, Max would be 100% a character choice.
Cons: mechanically he would bring nothing to the quest at least on paper (maybe some narrative bonuses to some rolls but those are very unreliable), and its something that he would absolutely hate, he would still do it but it seems cruel that knowing that he wants nothing to do with this kind of high risk nonsense when given the chance we send straight back into it. (and you know, the risk to his person considering the situation but that goes for anybody that is sent in the quest)
Pros: The whole teacher/student thing that Russ and Max have going on and more than anything Max would probably bounce amazingly with Bonkers narrative wise
While for me Ludivine is more of a mechanical choice (better learning), having said that putting her on the quest would probably give more opportunities too show her character and interactions.
[X] Plan: Toons and Competence
Is my current vote but I might change it depending of how the conversation goes