You don't think this would expose it to employer capture?

Not anymore than the current system? I'm talking about the employee side of payroll tax to be clear see Oren Cass (his specific idea is a little bit weird because its based on hourly wages not income, I don't think that's a good idea but the other parts are fine).

How would the minimum wage prevent capture?

How do you decrease wages when there's a price floor on wages? Like sure you could cut hours but as far as I'm aware the minwage lit says the effect on quantity of hours worked usually aren't enough to offset the higher wage.

Note that the Saez article that prompted this discussion is also mostly concerned with lower wages, not lower hours.

Why would you have a minimum wage when NIT addresses the same problem?

One decreases incentives to work and one doesn't. NIT addresses a different problem - those who can't work at all have the highest poverty rates. Wage subsidies just mitigate the disemployment effects of NIT for the rest of the population.