his title and estate, at the same time married Lady Dorothea."

This sounds like Manfred in 'The Castle of Otranto' who wanted to marry the woman intended for his son, for an heir.

I agree with terimc's quotes from the introduction in her book that this is more a satire on the types of books written at that time rather than the society.

Manfred's wishes ended tragically, but here Sir Edward's "wishes have been granted".

It seems by that age JA must have read quite a lot.