Interesting question Tarn, I think I can give an idea about a few of the individuals mentioned. World War Two is another area of interest for me, particularly since my Grandfather fought in the European theatre of the war, and my Great Uncle fought in the South Pacific.
I'm not sure about what Hermann Goering would have been doing prior to 1912, although his father was ill and died in 1913 I believe. He was not commissioned in the infantry until 1914 or 1915, then became a pilot. Rudolph Hess would have most likely been in boarding school, or studying business, which his father pressured him into, and which he was doing before getting involved in politics. He really wanted to be an astronomer. Goebbels had severe health problems as a child, and had been rejected from serving in WWI due to permanent physical problems as a result. I'm not sure exactly what he would have been doing at the time. Eichman would only have been a child, somewhere between 4-6 years old if I am recalling correctly, so most likely he wasn't doing anything noteworthy at the time.
Rommel would have just finished cadet training school, and was commissioned as an officer sometime in 1912 I think. I think that Himmler would still have been in school, but really am not sure.
It is odd thinking that many of these individuals who grew up to commit horrendous acts and become such terrible people started out life in a seemingly ordinary fashion. In the case of Hitler and Hess, if the former had been accepted into art school, and if Hess had become an astronomer, then history very well might have turned out entirely different. If Goebbels had been accepted into the military, it is possible he might have died in WWI.
Odd how things work out, the situation and economic/living conditions in Germany as a result of the way WWI was resolved really left it as a powder keg waiting for a match to ignite it. If these madmen had not come along, some other terrible person with influence may have, possibly one of the communist groups, or socialists. Would WWII have happened, albeit in a vastly different way if the Nazis did not come to power? Certainly, the war in the Pacific, which was already underway before Europe, would still have happened to some degree, but would Europe have exploded into war the way it did? It is a conversation that historians could have for days.
Kind regards,
Tad