Just a heads up, it has been confirmed by multiple people (on GAF and elsewhere) that the DLC content is NOT all post-game, as Nintendo had stated
Aspects such as the extra customization parts and the pet birds are available at exactly the same time as they were in the Japanese version. (Upon starting, and from the first town onwards, respectively.) Not all content has been confirmed yet, but I think it's safe to assume that the game will play the same as it did in Japan. (ie. Origin Island itself, and all content directly related to it, will still be post-game.)
Pretty poor job on Nintendo's part explaining this, as I know the confusion had put some people off. So for anyone thinking it would be best to wait until after you beat the game to buy the DLC, I'd reconsider that choice now, as doing so will delay access to early game content.