Some quotes attributed to Isoroku Yamamoto:
“The fiercest serpent may be overcome by a swarm of ants.”
The fate of the Empire rests on this enterprise. Every man must devote himself totally to the task at hand."
Some quotes for the ANZACs:
“At present, the prime necessity is to ensure the defence of Australia itself. But it would be wrong to assume that throughout the duration of the war, our duty would continue to be as circumscribed as that.” - Prime Minister Robert Menzies, September 1939
“This is the gravest hour of our history. We have a heavy responsibility. I ask every Australian, man and woman, to go about their allotted tasks with full vigour and courage.” - Prime Minister John Curtin, December 1941
Force intact. Still fighting. Badly need boots, money, quinine, tommy gun, ammunition. - Message transmitted from Portuguese Timor to Darwin, April 1942
Some quotes for the Italians:
“The German soldier has astonished the world; the Italian Bersagliere has astonished the German soldier.” - Erwin Rommel, epitaph to the Italian soldier
Until face to face with the enemy, who inexorably advanced well protected toward sure prey, they cried with the last spark of life, “Long Live Italy!” - Gen. Rodolfo Graziani
The Graziani quote is probably too dark. You may have to go hunting in a university library for better quotes on the Italians. I suggest a small book, Hitler’s Italian Allies. Much of the material you are likely to find, if not from Mussolini, will come from Ciano, who was something of a dry wit as a diarist and therefore isn’t likely to give you anything very stirring.