Note, however, that in some places, it is OK to combine the name + title for disambiguity, instead of relying solely on the attachment of an ordinal number.
e.g. for your father's sister, who is the 3rd child, you could say either:
- 三姑 ("father's sister, 3rd in birth order"), or
- 艷姑 ("father's sister, Yan"), if she has the character "艷" in her name.
I also heard that it's customary to mention the titles instead of resp. names.
That is instead of saying Aunt Jane, they'd need to say a specific title in the father's or mother's hierarchy.