WRYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY ! *applies steamroller offscreen*
Also yes that will work but I have a few other alternatives, though this one will take a fair bit of legwork. The Aswang Project is an archiving website that focuses on pre-colonial mythology and folklore of the Philippines and has done extensive work in their research; they mix everything from word of mouth of native peoples, a backlog of historical documents written and produced by other archivists from decades of study, and applies geographic, anthropological, and historical context for these things. I'd like you to observe how they disseminate say, a Tikbalang for example.
I really love how they do it because they do it in stages:
1. Preliminaries: Where they tell you what the creature is, it's physical traits, and its most well known mannerisms and attitudes
2. Contextualization: By studying the anthropological and historical background of the home country they begin to piece together the creature from bits and snippets from different time periods and watch it slowly evolve into the horseheaded man-beast that it is today
3. Modern usage: Some of the consultants are also authors of local literature and they give their own examples of how they used the creature in their stories
4. Summary: Where they basically evaluate the historical and cultural significance of it, talk about how modern writers are beginning to see the value of the beast, and what it means for the greater scope of Philippine, Asian, and World Literature as a whole moving forward
I was lucky to come across the site and the links to it and I'm certain you'll find something similar to the site's equivalent for Chinese or Japanese lower mythology (which is what you should concentrate on if you're looking for beasts and monsters), and considering (especially for Japan) how well documented their mythology is, I think it'll be easier for you to track these down.
As a matter of respect and I guess awareness I'd suggest you try to track down the cultural and historical backgrounds of the creatures you'll end up borrowing for your literature. Libraries and other sources are gold mines for this information so best start looking there. Also try to find modern interpretations of them in local media; which I admit will be considerably difficult since there are language barriers, but I'm certain they'll still be found. In fact considering how Japan uses its creatures and iconography so often in anime and manga, I think any of those interpretations will be suitable for the task at hand.
In my own work in researching these things I've come to the conclusion that to borrow a mythical creature is to take a part of it's culture's identity and history; the Tikbalang wouldn't have a horse's head if not for Hindu influence; it wouldn't be demonized if not for the Spanish and the introduction of Christianity; it wouldn't have the common name of Tikbalang if not for the consolidation and homogenization of the creature in the early 20th century by anthropologists and historians; and nobody would probably care about it today if not for a shift towards indigenous stories and beliefs in the 90s which still resonates until today. You'll notice that those talking points I brought up are a very short summary of my country's history (Pre-Islamic/Pre-Colonial Era, Spanish Colonial Era, American Colonial Era, contemporary era) which is why some people can get understandably angry if these are misused; not only is the creature misrepresented, but also the culture it came from.
Understandably this will take a lot of reading on your part if you're unfamiliar with the culture you're borrowing from, and your [reader's] millage may vary on how good or bad your interpretation is. I personally believe you don't need to have encyclopedic knowledge of the creature and it's background to talk about it but as a matter of respect and to generate real, tangible cultural enrichment, I'd highly advise at least bringing what you know about the creature and it's background up to acknowledge its roots.