It makes sense to just call the creature what it is in its cultural context as opposed to trying to put an ill-fitting separate cultural notion on it, imo. If something is a taniwha it's a taniwha, and if someone is curious what a taniwha is they can look it up themselves and understand its a creature from a specific region's folklore.
I feel that trying to rename culturally-specific things that don't have a neat translation, like folkloric beings, is generally always poorly fitting. It's like when the qilin is called a unicorn, when a qilin is a fish-scaled deer or ox with lizardly facial features and no affiliation with femininity or maidenhood. So basically almost nothing like a unicorn.
I feel that trying to rename culturally-specific things that don't have a neat translation, like folkloric beings, is generally always poorly fitting. It's like when the qilin is called a unicorn, when a qilin is a fish-scaled deer or ox with lizardly facial features and no affiliation with femininity or maidenhood. So basically almost nothing like a unicorn.