To tag a fandom or original work?

This is one of those cases where I feel like things get murky when it comes to tagging.

So I got a silly idea to write a story based off my Build A Bear plushes. Just a silly, whimsical story that's more cozy fantasy than anything else.

Thing is, Build A Bear has no established canon outside of Glisten and the Merry Mission (which has a movie). These are all plushes, outfits, and names I've chosen specifically. Most have been built in the store, but some are secondhand from eBay and thrift stores.

The physical plushes are the basis, but the world, characters, etc are all things I'm building from scratch. The plushes have no personality unless I give it to them and there's no established canon universe for things BAB comes out with on a regular basis.

So...help?