Regarding current polling, as already said in truth the numbers dont matter much but what does matter is the mind share and perception that is being developed over time. This is what will work over the long haul. Continue the marketing and PR, hit the right points, use the right language, tone, etc. What is showing is that Trump is building a base, however while of some the base is being built on standard republican values, etc. key parts of it are not. They are being built on ideals related to a broken system, self preservation, growth of a nation, change, etc. This play, done right will/is having a broader appeal.
As for Hispanics, women, etc. While I don't think hes going to be the champion of their cause, I bet he gets growing support from them over time. Obviously these are just assumptions and guesses, but looking at it from a marketing/PR perspective I see Trump having certain phases in his campaign where he will go out of his way (to a degree) to clarify his views and tailor his message to those audiences.
For example, really drilling it home and possibly having some specific programs, etc where he can demonstrate how Hispanics (or whoever the target audience is) is part of his plan and when he says "Americans, he means them!" Obviously thats not going to sell everyone of that demographic but it will appeal to some. He'll start addressing those here legally with pride, playing on the hurdles they have overcome and "the hard work and dues they have paid" and why its unfair to them...etc
It's all in the framing and perception. Again many think its an all or nothing game when its been VERY clear that with Trump is the "Art of the deal"...and everything is a deal, a transaction, etc. It's pretty much in Trumps proverbial DNA. In campaigning, policy, life, etc...the man is flexible and always ready to pivot as needed to get the best deal in that moment. That doesn't mean he will always succeed but his track record at that is pretty good.