Hi
Are you referring to the reference in 1861
RG09, 3212, 73, 3
Elizabeth Simpson born 1845 Morton, the daughter in law (step daughter) of Robert Mann?
If so in answer to one of your queries, it looks like she possibly was illegitimate as it looks like the first time Jane Simpson married was 1847 to Jacob Anderson then to Robert Mann in 1854.
Evie