These 'Were-cassowaries' are a great idea and worth exploring, but I think they need more polish, detail, and mechanical work. However, this little pdf is Pay What You Want, so the author isn't asking much.

I think that with additional work and detail, these could become a very solid addition to Werewolf: The Apocalypse. As they are, I like them but do have some thematic and mechanical concerns.

The Good:

It's entirely plausible for Pentex to unleash these things on Australia. They're certainly an improvement over hypothetical dingo-based War Wolves, on a continent where wererhinos really won't work. Cassowaries are fierce and dangerous birds, and suitable stock for a Mockery Breed. The idea for how they turned towards Gaia is a good seed, and of all the Mockery Breeds they have the best chance of redemption. The name is also great - fitting and very 21st century. Overall, this is a great idea.

The Unpolished:

Thematically, the Murder Birds' redemption is too easy and complete for me. I think the Werewolf setting demands a much more arduous and unfinished path. Gaia immediately adopting a creation of Wyrm-industry and turning them into a full Changing-Breed without Wyrm-taint just isn't plausible to me - I think She would demand ages of service to Her before She'd bless and embrace them, if it's even possible. The mental realm they inhabit is a cool idea but would make more sense with an origin from a captured Mokole, rather than a Corax; a genuine Yathamaya would be a good explanation for learning about Gaia. Making their redemption and new allegiance an ongoing process, a path they have only started upon, would also create more possibilities for moral grey areas, conflict, and character/story development for Murder Bird PCs - or even for Gaian shapeshifters who want to help them.

Mechantically, I don't think it's plausible for them to have the full range of breeds and forms - no canon Mockery Breed has that, and I don't belive Pentex could pull that off. I'm not sure the powers are balanced, but they won't play in a mixed-Breed group, so maybe that doesn't matter.

Lastly, the layout isn't professional, and there's no artwork.

Conclusion:

With all that said, Murder Birds are worth using for any Werewolf game in Australia, Papua/New Guinea, Nusa Tenggara, or Maluku, either as player characters or as a completely unexpected mystery (and moral conundrum) for any Changing-Breed. As antagonists or wild cards, you could throw them at any WoD splat (except wraiths) and enjoy the players' confusion.