Do they need to know what FMLA and ADA are? Yes. Do they need to know how to administer all the details? No. If you spend too much time teaching them about the boring details of disability and leave of absence management you're going to lose your audience.
Stressful workplace changes, job changes, disciplinary action, attendance issues, and demotions can all cause an up-tick in FMLA cases and usage. Share information about large changes and escalated issues on a weekly basis across the entire HR team so that you can collaborate and prepare for the side effects of change management.