In re: the animals and their reaction (or lack thereof).
Generally speaking: cats aren't quite as reactive to strangers as other creatures. They are not going to respond to a stranger for the most part. They tend to be "as long as you leave me alone, I'm not going to even be interested..." with strangers. However, that being said, I have two that will approach strangers and ask for lovies...Oliver and Malachi. They are interested, but there is nothing about their interest which would ever be something I could count on to give me clues that there is a problem.
Newfoundlands, which one of their dogs is (Tessi), are notoriously friendly, charming, and laid back. There was exactly one time where she "protected" me, and even that was not an aggressive protection - just moving herself between me and who she considered a potential issue. And this was after the person had been hollering at me for a minute or two. She is valuable in home defense purely from size and appearance alone...her huge head goes into the window to "see" who's there, and the people who see her back off (once all the way to the street). But if Grace knows you, and you know her, she will say hi by pushing her head into your hand, and asking for lovies. LOL. And Newfs are just like that. They will save a stranger from danger, but if the stranger is danger...and/or she knows the intruder, she'd help carry things to the car, thinking she'd get to go on a ride.
As for my beagle, he's a scaredy cat. He will absolutely bark and let me know that there's something out there, but he won't confront them at all.
I believe (although haven't read it anywhere) Wylah is an Australian Cattle Dog. They are great working dogs, but will also defend their person. However, they are also very loyal dogs; if it's a person they know and trust, they very well might not do anything to protect their owner, simply because they know that person is a "friend".
Wylah was a puppy during this time, and was apparently very well socialized. She went a lot of places with Morgan, and was probably well known with her friends. Because of that, Wylah would not have thought those 'friends' were dangerous, even if they were, or were doing something dangerous to Morgan, because Wylah knew them as friends, and knew them from other locations and places.
I have to discount any questions about Tessi, the Ingram's Landseer Newf. And I have to think that either the puppy knew the person(s) who did this, or was not of an age where she would protect. Assuming the puppy was about 4 months when she was brought home in August, she would be very young when the stalking started, and only +/- 8 months when Morgan died. That, to me, is far too young to expect her to be able to protect, or to even understand what danger would be, and bark a lot at someone she knew and trusted as a friend (as that is who I think did this...a "friend" of Morgan, or at least someone she thought of as a friend).
And I have to discount the cat's response...there are no "guard cats" for a reason (but they are still valuable members of a family...and provide a ton of love and cuddles and laughter at their antics).
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Herding Cats