Will the project purse only work with its tokens?
It will be internal exchange on the platform. You can use cryptocurency and fiat money.
I understand that US residents were unable to participate in the ICO due to regulatory issues. I assume that will continue to be the case. How do you prevent US residents from acquiring tokens on the secondary market, subjecting you to SEC regulation without your knowledge?
They can not buy tokens on ICO. They can not pass KYC procedure. Secondary market is cryptocurency exchanges. They have there own KYC procedures.