A:AnswerYes, using the Files app on the iPad you can access files saved to a USB-C flash drive. If connecting a USB-A flash drive use the USB-C to USB-A adapter. (sold separately)
A:AnswerAt this point, probably best to wait for the next gen and hope they make more. I ordered a 12.9 1TB Wifi model for store pickup and it never arrived. There is a big shortage. Hopefully they make more of the ones they are about to release--those will have a mini-LED so it's best to just wait until March and hope for the best.
A:AnswerYes, in fact I presently have MS Office installed on my iPad and I use it daily. The advantage is that I can mark up slides and documents using the Apple Pencil, and there is a lot of other functionality that is not available on either the Windows or the OS X versions.
A:AnswerNot on the WiFi version. There is no Radio in the WiFi version, other than connecting to WiFi. However, have you ever really been anywhere in civilization where there is no WiFi? Right. Me either.