Here "name" stands for the person. The phrase "my name be named in them" is an idiom that means a person is remembered because of another person. This can be stated in active form. Alternate translation: "May people remember Abraham, Isaac, and me because of Ephraim and Manasseh" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-idiom]] and [[rc://en/ta/man/translate/figs-activepassive]])
Here "they" refers to Ephraim and Manasseh, but it stands for their descendants. Alternate translation: "May they have many descendants who will live all over the earth" (See: [[rc://en/ta/man/translate/figs-metonymy]])