Oh hey! Time to engage in my favorite internet pastime: rampant speculation.
So, when we were first attempting to figure out what to do with Sullivan’s journal entry that unlocked the Chronocompass, I was combing every resource I could find for mentions of Deirdre’s mother.
In addition to what you listed above, we know Aisling and Monica were best friends in school, and I feel like imagining a person Monica would have been good friends with gives me some ideas of what she may have been like. But since Deeds mentioned that Sullivan and Aisling had met when she was following the path of silver, I have to wonder how she picked up that thread in the first place.
Someone mentioned on the Fragment thread that we should probably distinguish between the group who created The Storm and the path of silver itself, and I categorically refuse to believe Aisling herself could have been involved with the Silver group’s nefarious plans to destroy those opening the Book of Briars. (I have lots of thoughts about them, too, but that’s mostly for another post.) However, knowing what we now know about the conflict between Monarch’s Mountain and the Silver makes me think.
This conflict has endured for generations, so clearly someone (or several someones) from the Silver passes down their knowledge of magic to the next generation, and I can’t imagine them letting their magical materials circulate just anywhere, jealous for power as they are. Thus, the most likely way I can imagine Aisling reaching the path of silver is through a relation; maybe a distant or estranged relative had some knowledge of the path, or of the magic in Neithernor, that got her started?