We must distinguish between identification with a community and the fact that a person is designated francophone or non-francophone. In principle, section 23 doesn't make this distinction and doesn't mention the term “francophone” or “anglophone”.
That said, paragraph 23(1)(a) concerns the first language learned in childhood and still understood at the time of the census, namely, the mother tongue. As I mentioned before, this is probably the most important criterion outside Quebec when it comes to determining the number.
Paragraph 23(1)(b) concerns the parent's language of primary school instruction. This information isn't available in the census. However, the question was asked as part of the survey on the vitality of official language minorities.
According to the third criteria, if a child of the family is attending or has attended a minority language school, the child's parents can send their other children to a minority language school, even if French isn't their mother tongue and they didn't receive primary school instruction in French.
As I said earlier, it's not really important to distinguish between who is and who isn't a francophone when implementing the provisions of section 23.