Does the user that reported the crash have analytics shared with developers turned off? If so you won't get a crash file. You can ask them to send you the file. You can get the file by going to settings privacy analytics analytics data

You can create an app without ever having an iPhone. All you need is a Mac.

The original source of the model should have a license that you can look at to see what uses are allowed.

You can include it in the reviewer notes.