Do all the snacks featured have real world counterparts?
All of the products featured in the show are at least representative of real-life product that have existed, in Japan.

The products featured in the titles of the first two episodes are:

Episode 1:


Umaibo
Potato Fry
Coffee Milk Candy
Young Donuts




Episode 2: 


Kinako-bou
Namaiki Beer
Flute Ramune
Menko, a game akin to Pogs.


Much of the culture and novelty of Dagashi is rooted in Japanese culture, making it very hard for those out of Japan to appreciate.