Council of Elrond

Hero and Minion decks may include items of the other alignment which may be played counting only half (and having their card texts ignored).
Can Hero / Minion decks include Fallen-Wizard items (Keys of Orthanc) under similar conditions (ignore card effect, have the MPs halved)?

No.
But if Wizard to Fallen-wizard Conversion option is in use then Wizard player may include them in sideboard.