Several librarians worked on this question.

1.
I called LAPD media relations and explained that I wanted information on the police response to the "Critical Mass" rally on August 15, 2000. They told me that I should email the department the information I wanted at pio@lapd.lacity.org Attn Officer Plows. I'm not sure about the police departments in other cities, but if the person asking the question calls the media relations department of the city and has the date of the ride, they might be able to get an answer.

2.
Most states have a Freedom of information act or a public information act. I looked and California and New York both have something. LA's budget is on their website and NY cities is available for a fee if you want it sent, or you can go and look at it in person for free. I'm guessing that if you contact the police department you'll be able to get a copy of the budget or find out where you can look at it.

3.
It's been over a month, but I'm not sure if your question was answered. Please resubmit if you need to ask another question and we will try to help you as best we can.

As regards your question, I imagine there is no accounting for how much money is being spent on whatever police initiative, though it is certain one could be assembled. My guess is, however, that you would have to know exactly how much staff time was spent, how much each officer is being paid, and other such information that is probably not available to the public and/or compiled by the department. In general, I believe contacting the department, and/or filing FOIA requests will get you started.

As for the last 2 questions, regarding protections offered to police officer whistleblowers, I believe the police department should be able to answer your questions.

I will be posting your question and our answers to the website shortly. Please check there to see if anyone has added comments.