when it comes to the question you ask in the last part of your review, my answer - as a 76-year-old German looking back to his schooldays - is that, yes, it certainly would have been possible to avoid the disaster of WW2. The Germans, even those who had voted for Hitler, were ready for a new beginning, certainly as far as Western Europe was concerned, and even the remaining bones of contention in the East could have been moved out of the way by peaceful means.
The Germans, right up to the late 1930s, had reasonably good relations with Poland (the French Ambassador to Berlin, André François-Poncet writes about this in his memoirs), they even made a film, in 1937, about the heroic fight of the Poles against the Tsarist occupation in the 19th century; the script was based on a Polish play and the on-location portions were shot in Warsaw.
Churchill, in spite of his excellent education in the classics, did not heed the warnings expressed by the Delphi oracle when some Greek adventurer wanted to know whether he should attack Persia; the message was: "If you cross the Halis, you will destroy a great empire" - in both cases the attack was launched and in both cases the attacker ruined his own kingdom. We are still cleaning up the debris.