Location: California Are These Workplace Practices Legal? Multiple Potential Labor Law Violations At A Restaurant

Location: California

I'm located in California and have concerns about several practices at the restaurant where I work. I'm trying to understand which of these are legal, what labor laws may be getting violated, and what steps employees can take to protect themselves.
Here are some of the issues I've personally experienced or witnessed:
Missed rest breaks: Employees are not consistently given their required paid 10-minute rest breaks during shifts.
Meal breaks: Management has employees take their unpaid 30-minute meal breaks whenever business is slow, even if that means taking them after the fifth hour of work (sometimes past the sixth hour).
Audio surveillance: Cameras throughout the restaurant appear to record audio, and management listens to employees' conversations. I'm wondering whether this is legal under California's privacy and recording laws.
Alcohol service and minors: Management allows employees under 21, including minors, to serve alcohol. Employees over 18 who do not have Responsible Beverage Service (RBS) certification are also encouraged to serve alcohol. Additionally, minors and other underage employees are allegedly allowed to purchase and consume alcohol at the restaurant.
Wage reduction without notice: Our hourly wages were changed and decreased without any formal written notice or explanation.
Late paychecks: Employees are supposed to receive their paychecks on Fridays, but payment is routinely delayed until the following Monday or Wednesday.
Potential overtime and timekeeping manipulation involving a minor: There is a 17-year-old high school student working what appears to be a full-time schedule. Management has him under with two payroll accounts, one under his own name and another under his guardian's name. And his hours are transferred between these accounts, to avoid paying overtime. He also works past midnight and sometimes clocks out in the early morning hours. I'm concerned about potential violations of California child labor laws, overtime requirements, and payroll reporting laws.
Terminations: Several employees have been fired without notice, sometimes for seemingly minor reasons, such as servers talking back to chefs.
My questions are:
Which of these practices potentially violate California labor laws?
Are there separate laws protecting employees who are minors, particularly regarding working past midnight and overtime?
Is it legal for an employer to maintain multiple payroll accounts to split or transfer an employee's hours?
What are the rules regarding audio recording employees in a private workplace in California?
What agencies should employees report these issues to (DLSE, California Labor Commissioner, ABC, etc.)?
If multiple employees are experiencing these issues, is there a way to report them collectively or file a wage claim?
What documentation should employees preserve before management becomes aware that they may be reporting these practices?
I'm not necessarily looking to pursue every issue individually. I want to understand the applicable laws, whether these practices are reportable, and what options employees have without putting their jobs at unnecessary risk.
Thank you for any guidance.