Did the show ever really delve into the backstories of the Angels past the first season, when we met Sabrina's ex and her dad?

We later learned that Jill had a sister, but what about their parents? And were there any other siblings?

Also, who were Kelly's biological parents? Was that tied into why they never saw Charlie?

I didn't see anything wrong with the writing.

Jill has a sister and she has an uncle and aunt. Jill also had a fiancee.

Kelly was an orphan but there was an episode where she had possibly found her father.

And most of the Angels had friends from the past.