This is an interesting thread, but I just don't see a united neutral Germany happening without a good deal of changes in the diplomatic positions by all the powers, and this includes France. It was difficult enough to get unification through in 1990. While it is a good point that Austria post 1955 would be a good model, Germany is a good deal more powerful than Austria. I could see it happening only with the occupying powers retaining and exercising a lot more rights to interfere in German domestic politics. I think a more disunited Germany is a more likely postwar scenario than an united Germany.
Also, if I remember correctly, West Germany neither rearmed nor joined NATO until the 1950s ITTL, while the unification and neutralization of Austria happened around the same time. And this was during period of relative relaxation of Cold War tensions. So I don't think there will be much apparent divergence between the Schumacher government and the Adendauer government initially, and a Schumacher government might be shortlived. It may not accomplish much then give way to a center-right government.
Also, if I remember correctly, West Germany neither rearmed nor joined NATO until the 1950s ITTL, while the unification and neutralization of Austria happened around the same time. And this was during period of relative relaxation of Cold War tensions. So I don't think there will be much apparent divergence between the Schumacher government and the Adendauer government initially, and a Schumacher government might be shortlived. It may not accomplish much then give way to a center-right government.