Inside Firefly, there is a UI option to place "footprints" (e.g., of astronomical instruments) over displayed images. Footprints are created from region files in the Firefly repo (https://github.com/Caltech-IPAC/firefly/tree/dev/src/firefly_data/footprint) and appear to be treated by Firefly as standard DS9 region files where the ra,dec coordinate system is treated as having a relocatable origin and orientation (i.e., as field angles rather than true ra and dec).
For (1), one possibility would be that the region file upload dialog might get a check-box added to it saying "make origin movable" or "treat as footprint". Alternatively, an "upload footprint" element might get added to the existing footprint menu.
Please see also tickets I've filed in the IRSA system, including IRSA-1612 and IRSA-1613, regarding the treatment of footprints and their coordinates in the layer dialog.