You own a business. You don’t have “regular income” right? I would take the results of the net price calculators with a grain of salt. Your actual results when considering a business could very much indicate you can pay way more than even what you got with the NPCs.
But the good news is you will not pay in excess of the full price.
You say you are full pay…but at what cost? $30,000 a year or $75,000 a year? If costs are a significant concern, your student needs to apply to less costly schools. Or the student needs to apply where significant merit aid (that doesn’t take finances into consideration) will be very possible or guaranteed.
Your student can submit a FAFSA after acceptance and after accepting the admission offer…if all they want is the federally funded student loan ($5500 for freshmen).
Re: what @happymomof1 wrote about not applying for need based aid in year one prohibiting you from doing so in subsequent years…that is the case only for a handful of colleges if you are a U.S citizen or permanent resident. So do check. This policy is very much present for international students at many, many colleges.