Who has more right to the custody of children (male and female) after the mother's death: the maternal grandmother or the paternal grandmother, with evidence from the Quran, Sunnah, and sayings of the Salaf?

Custody is for the maternal grandmother after the mother, according to the majority of scholars. Jurists differ on when it ends: The Hanafis believe it is for the male until he becomes independent (seven years), and for the female until she desires (nine years). The Malikis believe it is for the male until puberty, and for the female until marriage. The Shafi'is believe it continues until the age of discernment (seven years), then the child is given a choice. As for the Hanbalis, they believe it is obligatory for the father to have custody of the female from seven years until marriage for her protection. The preponderant view among the Hanbalis is that custody belongs to the father unless he is immoral. The details of custody and the conditions of the custodian are mentioned in books of Fiqh. In case of dispute, the matter is referred to the Sharia judiciary, and the cost of custody is from the ward's money or from whoever is obligated to support him.