Australia - 2 leaders: Sir Edmund Barton and Gordon McKenzie. Unique Unit: ANZAC soldier. Unique Building: War Memorial.
I'm sorry, but who is Gordon McKenzie? Do you mean Sir Robert Gordon Menzies, or is it just someone I haven't heard of? For Australia, I think Gough Whitlam and Robert Menzies would be better leaders, as they are more recognisable and (arguably) more important/better leaders.
Henry IV, Henry VIII and William the Conquerer would be good to see for England, and Eisenhower, JFK and Thomas Jefferson would be good to see for America.