In the first two scenarios, I presume the authorities would be informed because damage would have been done to the Watchtower itself and its property (the Kingdom Hall.) They would likely call the Legal Department before that, but the issue would be reported to the authorities right after.
In the third scenario, they would call the Legal Department to inquire what the law in their area requires. (Sounds ridiculous, but elders are idiots who don't understand anything, so they need to be told everything by the Watchtower.)
In the fourth scenario... you know the procedure. Legal Department, no authorities, innocent victims victimized, abuser protected or disfellowshipped (read: still protected) unless the investigation bears no results, in which case the matter would be left "in Jehovah's hands." (Keep in mind that when the letter mentions the two-witness rule, it says that if there is only one witness, the Legal Department should be called. What happens later, we don't know. The matter is probably left "in Jehovah's hands" as well. I don't think they would investigate when there are no two witnesses. After all, elders are usually idiots who are unable to think and have to be told everything by the Watchtower [see the Australian Royal Commission for irrefutable proof.])
In other words, hypocrisy...