is minority interest an extraordinary item?

Answer 1

No, it's not.

Minority interests should be presented in the consolidated balance sheet within equity, but separate from the parent's shareholders' equity. Minority interests in the profit or loss of the group should also be separately presented. [IAS 27.33]

Attached is the model financial statements from IASB. Take a look at the balance sheet to see how MI is presented under Equity and Liabilities (page 9)