They're still available to my knowledge. Just odd they're not shown on the website.
However, this website showcases every single Duffy costume release that's been done so far at TDS. The site is in Japanese, but if you use Firefox, it comes with Google Translate built in, so you have an idea of how to navigate.
Here's one of the outfits (t-shirt w/ Duffy on it, shorts, bucket hat & tote bag)
And the overalls, striped shirt, hat & tote bag
Couldn't find the travel set on there though.