From left to right:

Pumpkin Cake (daughter of Cupcake and Carrot Cake) [adult design by: JennieOo]
Princess Flurry Heart (daughter of Princess Cadance and Shining Armour) [adult design by: Pastel-Pony-Artist]
Cream Puff (daughter of Millie) [adult design by: first-flakes-of-snow]
Pound Cake (son of Cupcake and Carrot Cake) [here's the link to the Pinterest page: www.pinterest.com/pin/25128685…
Dipsy (no cannon parents) [the adult version no longer exists on DA, but here's a link to the page on Derpibooru: derpibooru.org/808811]
Apple Bud (no cannon parents)

The base is from a YouTube video, here's the link: www.youtube.com/watch?v=JwdxNI…

The website I used to make this is sketch.io/sketchpad-4.0/