Blacks love Hillary almost as much as they love Obama. This has become plainly obvious. They will not be a problem. Hispanics will not be a problem thanks to Trump, she'll most likely even improve on Obama. Her biggest problem is the young white millennials who may stay home or vote third party. She needs to staunch that bleeding as best as possible. Her other problem is that she's sure to fall among white men, particularly those with no college education, but this can be countered by improving among college educated white women.
This.
1. I think people really are underestimating Black turnout in Hillary's favor. Trump would likely accelerate turnout among this particular subgroup (at least slightly)
2. I am 100% sure that Latino turnout and margin for Hillary will increase, especially when we're dealing with Trump obviously. Like the AA community, Hillary does share a strong bond with the Latino community as well. Now if only they would vote like African Americans, Georgia and Arizona could flip in the near future (if not in this election).
3. The subgroup of Asian Americans are very likely to increase their margin for Hillary as well due to the clear trend.
4. It'll be interesting to see if Hillary can take the College-educated White vote though. It's hard to say at this point.
5. The only concern is how Millennials will turn out. There is no doubt that the ones who do will vote for Hillary heavily (even if they were Bernie supporters). The problem is that they turn out to the polls much lower than previous generations. I'm not too concerned with them voting for Attention Seeker Stein (a.k.a. A.S.S.) since polls tend to show that there is a lot more unity than what the media, Reddit, Twitter, etc. wants us to believe there acutually is.