Trump's favorable ratings with the general public are god-awful and in fact not any better than they were when he began his campaign (as any improvement with Republicans has been replaced by his ratings going into the tank with Dems/Indys). Hillary's are bad, too, but Trump's are way worse. He assures high minority turnout for Hillary, which otherwise would have been a concern for her.
His only chance to win is if there is a major economic meltdown or terrorist attack before the election. Even then, it's not assured.
Absolutely, completely not true - his favorables went from 15/76 to 39/59. His favorables were so bad that Nate Silver wrote him off completely.