Is there a definitive answer as to whose hand this is? I guess it could be his mother's.
No, and I that's my guess. Here's the quote:
Then something strange happened. Another hand took mine. The hand was slim, the fingers long and delicate. Feminine. The hand gently covered mine, and lifted it, like a small child's, until I held my mother's pentacle in my grasp.
I held it in my hand, felt its cool strength, its ordered and rational geometry. The five-pointed star within the circle was the ancient sign of white wizardry, the only remembrance of my mother. The cold strength of the pentacle gave me a chance, a moment to think again, to clear my head.
There are several times where there is a woman's voice or some such thing that comes to Harry's aid. Another time is
Death Masks, Chapter 15, Paragraph 3:
A woman who seemed familiar but whom I did not recognize shook her head and drew her hand from left to right. The dream-scenery faded to black in the wake of her motion. She turned to me, dark eyes intent and said, "You need to rest."
There is the time at the end of
Changes:
"Hush now," whispered a woman's voice. It sounded familiar.
And the obviously Dresden's mother one of the soulgaze with Thomas, but I don't know if we should count that one because it is not at all subtle as to who that is.
Am I missing any?
Who is a woman Harry would find familiar but not recognize? He has/had a photo of his mother and after the soulgaze, he has a permanent memory of her appearance and voice. Also, he immediately recognized her portrait in Raith Manor. But he should also recognize Lea and Mab.
In the first instance, Lea had power over Harry, so she could have sock puppeted his hand to the pentacle like Mab did with the letter opener, but that's not exactly what happened here.
