RR,
You will find a number of examples of EFIS aircraft in Oz that used defib. No known probles that I am aware of, no flight manual supplement restricting their use.
Every PC12 in oz used for Medivac is EFIS, and most of the B200s in the SE and WA parts of Oz used for medivac are EFIS.
The engineering managers of such organisations are normally more than happy to talk to people about their gear.