Yes you pay the #15 pick #15 money - and inherently a draft pick has never played a single NFL snap. Would you prefer a lesser player who is a poor fit for the team? Guess what, they still won't have played a NFL snap and you still have to pay them #15 money. (Unless you just refuse to sign him, basically forfeiting the draft pick for nothing. THAT will please the fan base!)
As for this Dunta not getting payed nonsense - he's getting $9.97 Million for one year! BOO HOO! That's more than he deserves but he had the Texans over a barrel by refusing the $23 Million contract - they either had to franchise him or lose him as a free agent. If my employee pays me $10 Million for my entire career I would be happy not whining.