quite a scenario !
let me make clear right away that i am NOT at all sympathetic with fashism!
but i have to ask you how you came to this conclusion?
hitler made a couple of reasonable claims that the other european countries would have had to accept without being backed up by the US. granted he might have declared war on poland eventually (which is not proven however) to get back the territory that was taken away from germany after the first war...but there is absolutely no evidence that would suggest that he would have attacked any other countries. russia was attacked after it became obvious that stalin had planned an attack against germany. and a war with the west was never wanted by hitler.
although it was terrible what happened to jews they were not killed deliberately before the war started...hitler tried to deport them to other countries including palestine.
from where do you get the idea that japan would have had attacked australia? knowing they would have to declare war on britain in this case? that seems strange. however i have to agree that japan did terrible things to the chinese and koreans. so this might justify taking action against them...although britain and france were not very nice to their colonies either and the question arises why these countries were allowed to occupy 2/3 of the world.