I would agree, though I would say the Democratic party is not tearing itself asunder the way the Republicans appear to be doing, but has politely shifted left. For avid observers of politics this could be a very interesting year.
No, it is not. They could very well be supporters of, variously Sanders, Clinton, Cruz, Rubio, or Kasich.
The Bern and Trump are on the same side of this coin,and a major reason The Bern won Michigan and may win Ohio tonight: "The Midwest has always been the heart of America―both its economic bellwether and the repository of its national identity. Now, in a newly globalized age, the Midwest is challenged as never before. InCaught in the Middle, longtime Chicago Tribune reporter Richard Longworth explores the new reality of life in today's heartland and reveals what these changes mean for the region―and the country."
It's pointless to speculate on the general this far in advance. Likely it will be determined by the battle in the summer to establish a negative persona for the opposing candidate. Obama did that very effectively to Romney in the summer of 2012 while Romney was taking a leisurely vacation. By the time he woke up, voters knew him as the heartless bastard who let a worker's wife die because he stole their insurance and forced his poor dog to ride on top of the car. The problem Hillary will have is all the dirt on Trump has already been thrown. His voters don't care. He will have survived a fullscale media attack for over a year. Hillary however has been riding the usual liberal wave of media adulation and coverup. When Trump hits her with the Benghazi mom and covering up Bill's abuse of women, it could get ugly. No one likes her anyway, not even her own supporters.