As I guessed, your budgets are on the lowish side. List their current ratings, because several of those projected ratings seem "cooked". who is Harper's agent? If its his mom, drop him unless you're willing to take the 2nd ovrall pick next year. If he has an agent, I'm fairly confident you can sign him w/ enough tries. If/when he official rejects your 1st offer and says he's going to college, offer him again his original demand. It may take 5 or more cycles of this, but eventually I think you can get him to sign, unless his mother is his agent, then I think he's likely to turn you down and not allow you to offer him again.
But, I'd want to see his current ratings first, as well as others, because he's likely not going to hit those ratings.