One of the ways to use an HC born after the PoD, In Personality Only is basically Fame Equals Birth where names are changed.
Fame doesn't always equal birth, but just because you weren't born doesn't mean you can't play a starring role. You just need to play that role under a different name. File it off, slap on a pseudonym, and hey presto! Be yourself In Personality Only.
Contrast with In Name Only, where a familiar name shows up on a very different person. Compare with an Timeline Twin ATL Twin, where the name and content are changed but the role stays the same.