What I want to know is the outcome of those 3 separate wars, not the probabilities of the wars starting.
Okay. Italy gets stomped trying to take on France and Britain by themselves.
Japan gets stomped trying to take on the British Empire and US without an European War.
Stalin, you'd probably see carving up slices of Poland, Romania and Finland and eating up the Baltic states almost OTL. Really would depend on Germany, who's in charge and what kind of state of armament they're in.
Without Hitler and a belligerant Germany, the balance of power is very different. Italy was more firmly in France and Britain's camp before Hitler rose to power, they likely would remain so. This means no adventures in the Balkans and such.
Japan is still going to be faced with the dilmenia of Go North or Go South as OTL, but South's gonna look a heck of a lot stronger.
If Stalin starts rattling is sabre in Eastern Europe, you likely could see all the great powers in Europe ally against him, which makes the North look like the better option in Japan's book.