Actually, that’s not the case … as explained here.
That’s correct.
Yes, but you can edit/change this Id in the sidecar/.dop file (you can change the name of associated image within the sidecar/.dop file too) and it will have no affect.
It’s only the file-name of the of the sidecar/.dop file that matters (it must match the image it’s related to) … the internal references within the sidecar/.dop file will be updated the next time PL sees them.
John M