It's certainly interesting that the switch triggers after Ayleen, I wasn't aware of that - but aren't the cats usually more linked to the Covert? There's a bunch of cats hanging on the hidden room at Damna's and IIRC some of their dialogue outside that still suggest it (but admittedly I can't recall a specific example)
The shadiest part of Ayleen IMO is that she had that one book. Svelva certainly isn't portrayed in a good light but realistically we know very little of 'em (do we even know if they're male or female? Not even the wiki clarifies).
In regards to Nalid, the fact that his name is literally just Dilan but in reverse makes it fairly obvious that he's some reflection of him. Between the gravestones, the book, the mindsink events and especially Person it's fairly clear that something happened in Dilan's past that we (and possibly him) know very little about.
Also while we're at it, while Person seems to dislike Dilan, his events mostly seem to be trying to reveal some kind of truth to him, so in a roundabout way he seems a bit more trustable than the usual Katalist character?
MINDER IS THE TRUE ALLY BTW MINDER SUPREMACY
Finally as for Hum, yeaaahh I don't know what to make of him. The disposition does say a lot and he technically does nothing wrong. But like he pretty much upfront tells you that he's hiding shit. He knew our name, so he's probably linked to the aforementioned mysterious past.
A couple more possible allies I forgot