1. Since the bash bunny is a linux box, you possible could install the adb-tools if they are not bigger than 2 gigabytes (which is the free space you have on your bunny). You shouldn't have to install the complete android toolset but just the adb-tools so I think that my fit.
2. Try to connect a normal keyboard to your mobile and enable debug mode using it. If you can do so, you can use the HID attack vector to enable debug mode.
3. There is already a unlock script for android in the ducky repo, maybe this will work for you. If not, you will have to find a way to unlock your phone /