It's still much too early and these polls can/will change. Question is which way? Some very interesting figures/stats can be read at the source link below.
Not going to happen and it would hurt Trump's one remote chance of victory: portraying the establishment of both parties as being totally corrupt, which they are.
Bernie still stands up better against Trump, due, I think, to his favorability ratings. He is an honest, honorable man, but he has yet to be exposed to the character assassination machine of the right. Hillary's negative numbers are due to the constant, mostly made up accusations of the right. I would expect Bernie's numbers to fall as much or more than Hillary's after that onslaught.