Sort of yes on the first point. There are some middle income jobs with benefits setups that don't have to pay as much of the payroll tax as entry-level workers.

The rebate makes it progressive-ish. Up to a point, lower income people will be effectively paying less, but at some point it will switch to wealthier people paying lower rates because they spend a lower percentage.

Like everything, it will be structured to bone normal workers the worst.