If you manage to avoid the Great Depression in the way you just described, keep in mind that you've also killed the Democratic Party as a national political party. The only reason why the Democratic Party survived as a national party is because the Great Depression forced organized labor and Northern workers into the Democratic camp under Roosevelt. Without it, the Democrats will simmer in their own juices, and where the labor movement and the political left in the North goes is anyone's guess. An American labor party? In all likelihood, yes. Probably won't unseat the Republicans until a major national crisis.
Yes. The modern-day Democratic Party was pretty much created by FDR and his New Deal Coalition. Remove the Great Depression and the New Deal, and the Democratic Party becomes a conservative Southern regional party. I think some kind of Socialist/Labor Party is likely to emerge and unite the most of the New Deal Coalition groups; minorities, unions, and liberals, essentially. The Republicans are probably going to become a more centrist/slightly right-leaning party, while the Democrats are probably going to be limited to Southern whites and extreme conservatives.