Is the paternal cousin considered a mahram to the girl who was breastfed by his wife, and are his children, whether from the wife who breastfed or from another wife, considered her siblings?

What is prohibited by fosterage is prohibited by lineage. So, if a girl is nursed by her paternal cousin's wife with five full, satisfying breastfeeds within the first two years of life, the paternal cousin's wife becomes her mother through fosterage, the paternal cousin becomes her father, and his children become her siblings.