A:AnswerProbably not. I have tried file transfer from iPhone to pc without much success in a native form. However, if you buy some app such as anytran or copytran … cost around 20$ would allow file transfers. There is a huge app business to allow iPhone file transfers because it is much more complicated than an android or windows based system. I think this lighting adopter only transfers photos I didn’t use it but use iCloud or one drive to move files in and out of iphone
A:AnswerSorry Bob, Apple doesn’t support Video out over lightning USB, you’ll need an Apple Lightning to Digital HDMI Adpater in order to mirror your display. You’ll want the official Apple Adapter too as the circuitry is quite complex and contains an actual micro computer which acts as an airplay device. Many cheap knock offs you may find online don’t actually work and/or can harm your device.
A:AnswerYes this should in theory work. The DAC you are using might have to support or work with Apple products in order to do so though. There are many DACs out there so it shouldn’t be to difficult to find someone who has tested your specific DAC already. Videos exist of various dacs being tested with the adapter mentioned and they work fine so I don’t see why yours wouldn’t.