DisneyBounding is an interesting thing where it both is and isn't sponsored by Disney.
Leslie Kay coined the term started it as a way to express a character in everyday wear through colors and symbols.
In the past few years it has exploded in popularity and the term has become a regular part of the Disney enthusiast community. Disney Style has partnered with Leslie and others to showcase bounding, including giving them a bonus feature spot in the most recent release of Snow White.
Disney has released merchandise to play into this trend, but they don't ever release "Disneybounding merchandise"
Then you have the popularity of Dapper Day - what started out as a group of friends in Disneyland has grown to multi-day, worldwide events. That has also merged with Disneybounding and new term called DapperBounding has emerged from it.
And Disney has caught on - thus the release of these vintage, character/attraction inspired outfits (the definition of dapperbounding)
Disney has not called this a disneybounding merch line - that was a fan blog addition. Again, not officially sponsoring Disneybounding, but taking the heart of it.