Really sorry to hear about your attempted theft and the damage incurred.
Sorry for the late response, looking through the manual every reference to releasing the EPB (for maintenance or use) involves switching the ignition on, which as you say isn't possible with your car due to the damage.
I can only suggest it goes on a lowloader via a crane, I can't think how else you can move it. Perhaps a quick call to your Fiat dealer for their thoughts?
2015 500X Pop Star, 1.4