I've been having a go at attempting editing FM classic. It's apparently possible on android but I've yet to get it working on my iPad.
On android you copy the badges/facepacks to the documents folder and then delete the cache at the below:
sdcard\Android\data\sportsinteractive.fm15\files\application_support\Sports Interactive\Football Manager 2015\Caches
On my jailbroken iPad I have found the documents folder(all documents folders have moved since ios8) but when I delete the caches folder the app will not launch. Wondering if anybody might have any ideas!