Twins run on both sides of the family (Roberts/Carson) and in nearly each generation: Tinka/Tutti and Todd (second generation), Chili and Pepper (third generation), Millisandra and Atticus Skipper and Anslem's children (fourth generation) and if it's ever considered canon for the series, then Stacie and the other Todd are also twins (also second generation).
In the "Thanksgiving" episode, when listing the things that they are thankful for, while Stacie is thankful for really tasty (if not decadent) desserts and Kelly/Chelsea is thankful for her imaginary friends and world. Seeing how much of a troubling home life they have due to having Barbie for a "big sister", it can look as though the former is eating her problems while the latter is living in a fantasy world to escape her troubles (and the latter's interpretation is further supported in the beginning of "The Future" where she observes a fight between Barbie and Stacie and immediately goes off to her "happy place").
According to "60," a simple act of Barbie refusing to sign a contract with Mattel could turn a sweet guy like Ken into a monster, as well as managing to conceive Skipper, Stacie, Chelsea, and Krissy in the alternate timeline of the present, despite allegedly being stuck in a loveless marriage before ultimately leaving her for Yasmin. One shudders to think of the details...
Any Tinka-less video from 2023 develops this after the viewer remembers that the year's first video, "The Unexpected Hiatus," ends by showing Tinka locked in jail for allegedly murdering Barbie. Her prolonged absence can only mean that no one has freed her yet.
