Can you post the link to the bulk import you’re referring to? It’ll be easier for me to answer your questions once I have that.
Match candidates are determined based the Location ID, taxonomy, and viewpoint (the side of the animal the photo is of).
From the match page, use the Project drop-down menu at the top of the page to select your project. This will display match candidates within that project.
If the same image exists on another encounter, removing the annotation won’t delete the image. I agree this isn’t intuitive or user-friendly, but it’s expected behavior.
The good news is that the latest Wildbook 10.6.0 release now lets users edit and reposition annotations. ARW is currently on Wildbook version 10.2.0 but is on track to receive an update in the next few months as we work to bring all Wildbooks on up to date.