The behind the scenes video had lavish scenes of the editor working on the footage shot on iPhone ... with Adobe Premiere.
Lots of shots of Davinci Resolve, didn't spot any Premier at a quick glance? But it's not unusual for both to be used on the same production
Further, Resolve is available on iPad now, and Black Magic have a film app on iPhone (that I think was shown in the BTS). So technically they could've edited on iOS if necessary.
On the photo side, Lightroom on iOS is pretty decent.