Are the daughters of a maternal aunt who were nursed by the mother considered Mahram, and what is the ruling regarding the sons of maternal uncles, both older and younger than them?

The maternal aunt who breastfed from your mother is considered your foster-sister, and her daughters are forbidden for you [to marry] because they are the daughters of your foster-sister, as the Prophet, peace and blessings be upon him, said: "What is forbidden by lineage is also forbidden by fosterage." As for your other maternal uncles and aunts, they are not affected by this aunt's breastfeeding, and you are permitted to marry their daughters. Whoever is breastfed by a woman becomes her foster-son, and this kinship does not extend to his siblings, or his other ascendants and descendants.