Maybe.
Perhaps like with Sweet Apple Acres, Pinkie's parents are very old and kind of act like a "granny smith" character and Inkie and Blinkie, now adults, mainly run the rock farm together.
Wait a sec. Perhaps when Trixie mentions that she had to work on a rock farm, she was working at Inkie and Blinkie's rock farm...
Maybe. But since the CMC all have their own role models (Apple Bloom: Applejack, Sweetie Belle: Rarity, Scootaloo: Rainbow Dash), perhaps Inkie and Blinkie could be role models to other fillies. Babs Seed, Diamond Tiara, Silver Spoon are all up for needing a role model. Maybe Inkie, Blinkie, and Pinkie could each be role models to each of those fillies.
Cute picture, by the way.