Accurately Documenting Dates of Attendance at Previous Institutions for Ph.D. Applications
The format on most applications is: "Date Attended: From-- to--" without the option of listing several date ranges. 


Just put your earliest attended date to your latest, unless it specifically asks for dates related to your AA. Don't overthink it!


  Because of this, it is also a bit confusing as to whether I should list my GPA from institution X at the degree confer date, or to list my cumulative GPA 


Again, unless it specifically asks for your AA GPA, I would list your cumulative (I assume it's not much different in any case).

Details of your associate's degree are not going to be a deciding factor in your PhD admissions. Plus, it's likely your transcript lists your AA and cumulative GPA separately anyway (mine from my four-year undergraduate university does), if they truly care.