I would like to have more information about the Christianization of Somalia. I'm not so sure it was that relevant.
As to the start of Barbarossa, already addressed previously. At most, a couple of weeks can be gained.
Yes, the Germans have more resources to pour in the East front cauldron, but they do not have more fuel, so supporting the additional forces might be difficult enough as to essentially rebalancing their contribution to little more than OTL.
Naturally, come the winter of 1942, somebody will have to man the lines that in OTL were held by Italian infantry. They were no more than speed bumps for the Soviet tanks, but nevertheless they have to be replaced in this ATL. Yes, the Germans can use the troops they had deployed to Greece, Yugoslavia, Africa etc., but the assumption as to the Balkans is that the British in this ATL don't manage to churn up mischief there. If they do succeed, on the contrary, then Germany has to intervene.
In 1943-44, the Germans don't have to commit forces to Italy - but the same will be true for the Allies.
So no, overall I don't think the war lasts one more year. There is a possibility the nukes get used in Germany, yes, because even a three-month delay might bring that about. A collapse of the Soviet Union, just no.