You can't play FLV files in their original forms on the iPad Mini 2 device. Before you can play the files, install a compatible converter through the database of Software Informer and then convert the FLV files using the iPad Mini profiles found within the software. After this process, transfer the converted files to your iPad Mini device and they should be available for playback.
The listed applications will convert the FLV video files to the default file format supported by the iOS operating system.