@RWDS
Playing as Hungary or Romania also interests me, considering their history relative to Germany before the world war, and with this set up, after it.
Succession after Hitler is interesting for Germany, and I genuinely am not sure how it would be done if I took the German state. I would presume he died of old age, which meant he probably had a well thought out and planned successor. There are a few likely suspects, but it'd take some thought and some research on the subject to go beyond "it's Goring"
For the US, having a non-FDR president seems really interesting. If we're allowed to set the history between the wars end and now, it'd be cool to see a more right aligned America rather than the current left aligned one. This America lacks FDR and his new deal precedents that sort of shaped the direction the US went politically. I could also see the presumed survival of Patton being important too, with the possibility of him entering into politics during the early Cold War.
The scenarios that you came up with regarding the US and Nazi Germany are both incredibly interesting. If I had to pick one, a more Right-Wing America would be a very interesting dynamic with the other countries, espicially if they would decide to go with a "lesser evil" type of deal with their alliances and would decide to at least be neutral with one of the other Factions.