Legal Question in Business Law in California

You can get information about the owners of any LLC from the Secretary of State's office, which you can access via the State of California website. There may be a nominal fee if you need hard copies of certification. This would apply to a company doing business in California, even if it was formed elsewhere. (If it is doing business here, but not "qualified" by the Secretary of State, then it has a problem.)

Generally, you can't add defendants after a judgment is obtained and piercing the "corporate veil" may be difficult. You should consult with an attorney about the technicalities of doing so. They will need to review the particulars of the LLC and your claims.