I'm not aware of any additional legal obligations althought they probably vary from state to state but you have to start acting like a real company. My company is going through this right now. We're having to document everything, have written employee reviews, have folders of each employee, etc. If we have to let someone go, we have to document everything such as all the incidents and events that led up to the termination. We also have to spend time putting in structure to the personnel. Hope this helps.

The Family & Medical Leave Act (FMLA) applies to your company if you employ over 50 employees within 75 miles of the worksite, and at least 50 of your employees work 20 or more work-weeks in the current or preceding calendar year. If your company is a public agency, you are subject to provide FMLA regardless of the number of employees employed. All schools, private or public, are considered public agencies. As per my knowledge FMLA includes everything there is nothing more than this, that you need to comply with; i.e. taxes, filings, etc. Read properly everything related to FMLA and Employer, FMLA and Employees. Hope it helps you.

You might check the web site of the U.S. Department of Labor. They list the federal requirements for employers. Your state department of labor should have information on any additional state requirements. If you have not yet implimented employee handbooks, having them will significantly help with employee issues. Each employee reads and signs the handbook and it becomes part of their personnel record. When an issue arises that violates written company policy, the employee can't claim they didn't know. Handbooks can cover any and every issue that may affect your business, such as employee use of computers and company vehicles, dress code, employee conduct, vacation policy and more. It is particularly important to have a written harrassment policy, since the government holds the employer responsible for the actions of their employees. If you have a zero tolerance policy and you clearly articulate it to employees, they have no excuses for misconduct.