Yahweh uses a question to emphasize that the idols have not told them these things. Alternate translation: "None of your idols has told this to you." (See: [[rc://en/ta/man/translate/figs-rquestion]])
Here "ally" refers to Cyrus. Both of these sentences mean the same thing and are used for emphasis. (See: [[rc://en/ta/man/translate/figs-parallelism]])