1. When performance on a Federal Government contract occurs in the state of California on a short-term basis (normally 14 days or less), do the California Labor laws apply (specifically double overtime laws after 12 hours in a given day) to that performance if the company is not based in the state of California?  
2. When performance on a Federal Government contract occurs outside the state of California on a short-term basis (normally 14 days or less), do the California Labor laws apply (specifically double overtime laws after 12 hours in a given day) to that performance if the company is a California based company?

I am providing the following link.  I think your questions are best directed to the State of California agency that is represented by the website link.

https://www.dir.ca.gov/dlse/faq_minimumwage.htm

I agree with Carl Culham.

i found some sites that discuss the situations you described.

If you are wondering about Federal versus State coverage of labor laws, note that there are exceptions to Federal Supremacy issues, in particular for Labor laws. For instance, see https://uniontrack.com/blog/federal-and-state-labor-laws#:~:text=Article 6 of the U.S.,explains Andrew Latham at Chron.

California is one prominent example.

However, I would advise you to contact the state  labor agency or an attorney.

I believe I know the answer to Question #2 but as these are legal questions -- and I am not an attorney versed in labor law let alone an attorney of any kind -- I'm going to pass. There are hundreds of lawyers who can advise Anonymous FS; I recommend he go to one of them with his questions.