Louisa Cook (Joyce) - Parents of Louisa?

Sorces are suggesting that Louisa's father is a William Joyce rather than a John Joyce.
If so, this would mean that Louisa is not a sister of John J. Joyce, Free Settler "Success" 1843 and Elizabeth Burgess, Free Settler "Success" 1843 but maybe a cousin or step sister.
Noted that Louisa and Elizabeth married brothers from the same Burgess family.