I wasn’t sure where to look for this information, so I’d appreciate it if someone could let me know.

A reshoot and re-registration are two different things. If it’s a reshoot, you’re simply having your photos taken while remaining an active member, so I don’t think the concept of “failing” really applies. If it’s re-registration, there will be an explanation similar to the interview, along with another screening, so it is possible not to pass. That said, people who were previously registered almost never get rejected—unless they caused some kind of problem or didn’t receive any offers last time. If this was a reshoot, something probably went wrong, so you should contact them and ask what happened. In rare cases, the data on the SD card may become corrupted and they may be taking time trying to recover it with repair software. But usually, the work has simply stalled somewhere, and contacting them can help identify where things stopped.

I don’t think you need to worry about being dropped when it comes time to renew. You should be fine unless something particularly serious happens.

No, I don’t think that’s the case. You should probably contact them via LINE.