The title has 2 possible meanings Oshi means "to Push" or Support. Ko is usually used to refer to a person or a Girl. Putting them together means "the Girl that Supports you" in reference to Ai supporting Ruby & Aqua in their past lives as an Idol. However, Oshi is also often a term used by Idol fans for their Favorite Idols that they Support & Ko can be a term for "Child". Meaning the title can also be said as "the Child of the Idol you Support." In reference to Ruby & Aqua's new lives as AI's Children.
It is Theorized that Peiyon, the Chicken Muscle builder from Episode 5, & the Kaguya: Love is War character Kazeno, the Cheer Club Captain, are one in the same. They're both Burley in physique, are known for Working out, enjoy Idols, & Share a Voice actor in Taishi Murata.
Note: Episode 1 Mother and Children was pre-screened in advance in Japanese theaters on March 17, 2023. The regular TV broadcast begins on April 12, 2023. The first episode has an extended runtime of ~82 minutes.
Adaptation of the the Japanese manga series of the same name written by Aka Akasaka and illustrated by Mengo Yokoyari.