I'm only a reader here at the Fimfiction but I would like to share this Idea I got today on the way to my workplace.
I don't know why but I was thinking about Babs Seed today and my headcanon about her being the youngest daughter of the of the Oranges. I believe she is the black sheep of her family and unfortunately, she isn't as lucky in life with friends as her cousin Apple Bloom.
Living in Manehatten isn't easy we know that from Rarity so I can easily imagine that Babs Seed found herself dropped out from the local CMC by her so-called friends.
By the time of the ending of Season 8 is a lonely teenager so when she hears about the School of Friendship from Apple Bloom she decides to write to Applejack and Princess Twilight to allow her to join to the school to learn how to make real friends.

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I honestly can't see why this isn't an option. Plus, Babs hasn't been seen in years even after she got her Mark as a haircutter. This could be interesting development.