1) I could not find anything on the AZ Labor Board sight that stated you had to meet certian requirements to be salaried. The only law that I found is that the employer must pay employees every 2 weeks (salary or hourly employees alike) unless the employer's principal place of buisness is out of AZ then they can pay monthly.
2) AZ does not have any overtime laws. There is only a minimum wage law. So for overtime the employer is required to follow the federal law (fair labor standards act). So if you are salaried and qualify as exempt under the federal law the employer can require you to work 50 hours one week and not pay overtime, then only have work for 10 hours the next, but they are not requird to pay you for the 30 hours missed in that week unless you have paid personal time to cover the missed hours. With few exceptions, to be exempt an employee must (a) be paid at least $23,600 per year ($455 per week), and (b) be paid on a salary basis, and also (c) perform exempt job duties. These requirements are outlined in the FLSA Regulations (promulgated by the U.S. Department of Labor).
There are three typical categories of exempt job duties, called "executive," "professional," and "administrative."
The job duties of the traditional "learned professions" are exempt. These include lawyers, doctors, dentists, teachers, architects, clergy. Also included are registered nurses (but not LPNs), accountants (but not bookkeepers), engineers (who have engineering degrees or the equivalent and perform work of the sort usually performed by licensed professional engineers), actuaries, scientists (but not technicians), pharmacists, and other employees who perform work requiring "advanced knowledge" similar to that historically associated with the traditional learned professions.
Professionally exempt work means work which is predominantly intellectual, requires specialized education, and involves the exercise of discretion and judgment. Professionally exempt workers must have education beyond high school, and usually beyond college, in fields that are distinguished from (more "academic" than) the mechanical arts or skilled trades. Advanced degrees are the most common measure of this, but are not absolutely necessary if an employee has attained a similar level of advanced education through other means (and perform essentially the same kind of work as similar employees who do have advanced degrees). In my understanding you meet the test as having a professional job and are paid on salary and as long as it is more than $455 per week, you are an exempt employee.
Under AZ law an employer may only withhold an employee's wages when the employer is required by state or federal law, the employer has the employee's prior written authorization, or there is a reasonable good faith dispute as to the amount of wages due, including the amount of any counterclaim, reimbursement, recoupment or set-off asserted by the employer.
Since you are exempt and salaried by law the employer only has to pay you for time worked so he can dock your pay for hours not worked in a week even if it was due to him closing the office.