Earlier quoted context omitted.
"To my mother, Ayn Rand and my daughter" is not ambiguous without the Oxford comma, but would be with it.
That seems ambiguous to me. Is the mother Ayn Rand or not? The presence of the Oxford comma, or lack thereof doesn't seem to affect the ambiguity.
- Ayn Rand can't be in apposition of my mother as there's no comma setting Ayn Rand off from my daughter
- Similarly, Ayn Rand and my daughter are not in apposition
- my daughter and my mother are mutually exclusive
This is described in more detail here:
https://en.wikipedia.org/wiki/Serial_comma#Ambiguity
> "To my mother, Ayn Rand, and my daughter"
Adding the Oxford comma creates ambiguity between my mother and Ayn Rand, unless the speaker is Ayn Rand's daughter.