Use your email account instead of the username they sent. that let me login. what a mess

Does the October score cancellation preview option extend to all test takers or only first-time takers?

I think you're on the right track. The flaw in the example you provided is that just because we (the readers) are knowledgeable of the fact that cats are vicious predators, Anna does not necessarily know this fact. If Anna does not know this fact, then we cannot say that she knows Brenda's cat is a vicious predator, she merely knows that Brenda owns a cat.

A similar example, related to this type of flaw and which appeared in one of the early LSATs, goes something like this:

The bank processes all checks on the very day they were dropped off as long as they were dropped off before 3pm. Mike dropped off his check at 2pm, therefore Mike knows that his check will be processed today.

In this case, we don't know that Mike knows his check will be processed. All we know is that (1) Mike dropped off the check and (2) it will be processed today. We have no awareness of what is going on in Mike's head.

Does that help?

Out of curiosity, how many pages are provided in the packet?