Will the IPad 2 Mini work with the Phantom 4?

Yes, it's on the approved DJI list of devices.
APP / LIVE VIEW

iOS Version v3.0.0.
Requires iOS 8.0 or later. Compatible with iPhone 5s, iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus,iPod touch 6,iPad Pro, iPad Air, iPad Air Wi-Fi + Cellular, iPad mini 2, iPad mini 2 Wi-Fi + Cellular, iPad Air 2, iPad Air 2 Wi-Fi + Cellular, iPad mini 3, iPad mini 3 Wi-Fi + Cellular, iPad mini 4, and iPad mini 4 Wi-Fi + Cellular. This app is optimized for iPhone 5s, iPhone 6, iPhone 6 Plus, iPhone 6s and iPhone 6s Plus.
Android Version v2.9.1.
Requires Android 4.1.2 or later.Compatible with Samsung tabs 705c, Samsung S6, Samsung S5, Samsung NOTE4, Samsung NOTE3, Google Nexus 9, Google Nexus 7 II, Ascend Mate7, Huawei P8 Max, Huawei Mate 8, Nubia Z7 mini, Sony Xperia Z3, MI 3, MI PAD, Smartisan T1.

RedHotPoker

Just like RedHotPoker said and hope you enjoy your flight.