I got all of the available ambiio for the game on the same day they came out here in the UK, and I got Isabelle and Digby with the game.
Isabelle just received her own CPSIA cert. in the US so she'll be getting an individual release soon
Australia + some UK countries have individual Isabelle & Digby, so you can buy it online from there if you want. But eventually the US will sell them individually as well c:
Some 'UK' countries?
Do you mean EU?
Things don't tend to have separate release dates for different parts of the UK...It would be pretty weird if these, of all things, did.
Isabelle just received her own CPSIA cert. in the US so she'll be getting an individual release soon
What's CPSIA?
I didn't know, either, so I checked and found this: Children's Product Certificate 102685
Digby is also in a limited bundle in Japan, while sold individually, Isabelle is also sold individually there too. They'll highly likely release Digby and Isabelle alone like they did there, it's just a matter of time, probably into 2016 after the holiday rush so people bought the higher priced combo instead of just 1 or 2 amiibo- they're a business after all, trying to make money off this amiibo craze.