Butcher is heavily retconning events so this is offered without warranty.
I agree. I first became sure that there was significant retconning going on during the exchange between Harry and Stacy back in, IIRC,
Small Favor. I consider it fairly sure retconning because of Harry's reaction. Luccio was talking to Harry about his mother, and what she was telling him was totally at variance with what he had heard from Eb, from Thomas, from Nicodemus, from Chaunzoggoroth, etc. It doesn't even match what her own simulacrum said to him in the story where he learns Thomas is his brother.
Now Stacy could have been lying, or trying to spare Harry's feelings if she didn't know what he already knew, but Harry ought to have reacted internally to this strange discrepancy. Instead, he takes it in stride as if it was natural. That tells me that JB was retconning Margaret LeFay's backstory.
Was Margaret playing a double or triple game, for someone? Possibly. It's also possible that she started out with misguided idealism and got in over her head, and became corrupted. That would fit with her 'shadow's comments that "I was so arrogant".
As for contact with Eb...Margaret may well have run from Eb, out of fear or shame or both, but that doesn't mean Eb couldn't have tracked her down. Likewise, he may have 'had his orders' regarding her, but that doesn't mean he
obeyed them. It might be that Eb contacted her in spite of her running, or at least monitored her and Malcolm from a distance. We just don't know.
But yeah, the retcon tangles up all the speculations.