Yes, if he/she wants to. It's a good way to show the boss what a hard worker and team pleay he/she is.
No. Hourly employees must be paid for the time they work.
Maybe. If the employee really wants to, then it's the employees decision to work without pay.
Yes. Employees are still being compensated for the time they work but they are getting it as additional time off instead of pay.
No. Employers can't substitute compe time for overtime for hourly employees.
Yes. Employees have a right to speak out about working conditions
No. The employer has the right to cotnrol what is said and done at the company.
Maybe. If you don't think it will do any harm, but if you don't like what the employee says you can stop it.