Deductions & credits

" If I paid $6000 in properties in 2017, and then received the tax relief check from NJ for $200, should the
amount of prop. taxes taken as a deduction be $5800?"
Obviously, yes. The point of the "Freeze" is to limit your property tax. You can only deduct property taxes paid.

The homestead rebate also reduces the amount of property tax paid. In the old days when it was also mailed, many New Jerseyans would deduct it anyway, so now it goes straight to the tax collector.

This is not an issue if you don't itemize. Many seniors don't itemize. After 2017, even more seniors, and others, will not be itemizing.