I live in an area full of stories. The Yowie, Tasmanian Tigers, Plesiosaurs, Big Cats.
I think the Yowie is a reference to Early Aboriginal settlers crossing paths with other humanoids as they travelled, possibly Neanderthals and it getting passed down and exaggerated in their oral history. Recent sightings are probably pissed farmers.
Tasmanian Tigers could still survive in areas such as this, millions of acres, much of it remote and impassable, it's possible small groups survive. Sightings are quite common. Not sure how many are just brindle Greyhounds.
The Hawkesbury River has long had stories of a monster, oral history of some Aboriginal tribes describe a creature that sounds very similar to Nessie, it could also be the origin of the bunyip myth. Modern sightings go back to the first white settlers. One odd point is that the mouth of the Hawkesbury is similar to Loch Ness in that it has many underground beaches and caverns. Personally I think people saw a big Bull shark which isn't common but does happen once in a while.
Where I live is pretty close to an Air base, in WW2 some American crews had big cats as mascots, the story goes that upon leaving they let them free in the Blue Mountains. Now this I believe, sheep and other livestock have been found up in trees, a common way for Leopards to store food. The Blue Mountains are vast and it would be easy to avoid all human contact.
So the two that are possible aren't really cryptids as one is an invasive species and the other an extinct one.
