Can you subpoena a company's FORMER employees for a deposition if the company is currently represented by counsel?

Please see Rule 30(a) of the Arizona Rules of Civil Procedure. The testimony of Parties in the litigation and their expert witnesses may be taken by deposition. No other depositions shall be taken except upon agreement by the parties or a court order. It sounds like you are trying to sue a company, that is necessarily represented, and you are representing yourself. I believe you should seek representation by a local attorney.

While it is true that no depositions can be taken except of parties and experts without consent of parties, or an court order, it is difficult to envision a scenario where a court would not allow you to depose former employees or current employees who may have information relevant to the claims. That being said, the normal course would be to reqeust the depositions of the former and currrent employees from the attorney for the company. If the attorney does not agree to produce the former employees (or cannot produce them because they are former employees) a subpoena would be appropriate. Absent some unusual circumstances the company, through its attorney would have an obligation to produce the current employees for a deposition.