I notice the Orlando Sentinel article says it's 12 people, but it's actually 13. There are 5, not 4, from the fire department.
The article also says 'eight Sanford cops'. One of the 'cops' is Crime Scene Technician Diana Smith. Such technicians are usually civilian employees.
Livingston is included, and also Ciesla and Santiago. With Ayala, Raimondo, and Smith, that seems to be everyone related to finding and collecting the items on Martin's person, except for the Medical Examiner's people and Sgt. McCoy
Of course more names may surface. Ayala didn't mention seeing the button in his report. That came out in his SAO interview. And the person who put the beverage can on the blanket remains unidentified.