Molly

'Information found online is most likely outdated. All information is to be changed following theory debunk streams, upcoming Patreon comics, and the pilot.'

Molly will not appear in Hazbin Hotel's pilot, but is canonically Angel Dust's sister.

Trivia
She may appear later in the series, or at the very least referenced, according to the recent Sept. 1 Q&A stream. A speculation is that her name never changed, so if stayed the same from the living world. Another speculation is that she shot herself in the mouth, after Angel's death. This is more than likely un-canon, however, there is a small chance that it is.