Yikes. I'd caution the use of the ACE medical system with Ravage. ACE has a different damage/injury system to Ravage and they're not compatible.
The main problem is zombie damage. ArmA 3 doesn't have any melee damage in it (and neither does ACE), so Ravage adds its own. If you get hit by a zombie, the damage you take can't be repaired by any ACE medical supplies. Likewise, if you take ACE damage (for instance, an avulsion injury), then Ravage medical supplies won't fix it. The latter isn't so much of a problem, but the former is.
So yeah, before you get into trying to switch units, I think you might want to reconsider what you're trying to do. You might be better off ditching Ravage and using Zombies and Demons instead as it may be more compatible with ACE (not that I know that for sure).