So HoloLens is stupid in that it only recognizes one FilePicker at a time (no matter how many may be installed). I don't believe the developers are going to try making multiple filepickers work.
So, I'm trying to figure out my own filepicker in an attempt to be a proxy-select for other filepickers.
In essence, I want to make a filepicker chooser that appears as a typical filepicker (if that makes sense).
Trouble is, it doesn't appear possible to get a list of pickers installed!
Am I experiencing a pipe dream, or is there a way to invoke a picker from a list of pickers?