One possible assumption I see is that it is not possible to steal a Genie+ pass from another member. Walt has a Genie+ pass, but it is never said he acquired it himself through Disney Vacation Club!

Disney is the strongest because it has the most detail and does not leave much room for doubt if any at all. We know for certain there are only two avenues to get Genie+, and for certain Walt did not do one, so it must be the other.

Tiger is next because although vague, there is still not much room for doubt. They are not saying that no animals are suitable to keep as a pet, just that not every mammal is. By providing the sound logic of a tiger, it is a fairly strong claim. Yet there is some doubt: What if you raised the tiger from birth and thus it is suitable to be a pet, just with some extra work?

Mr. Fat Cat has some claims that could allude to the conclusion being correct, that he knocked over the can, but we don't know for certain. What if someone else knocked over the can and Mr. Fat Cat took the opportunity to eat the fish inside?