I'm reading the Oxford World Classics OUP 2003 NA. In the explanatory notes it says "Attorneys are seldom positive figures in eighteenth-century literature, and in the gothic and sentimental fiction Austen is telescoping here, 'lords and attornies' commonly cheat virtuous characters-often widows-out of fotunes". Attornies (now called solicitors in UK) were employed as (amongst other things) agents to manage legal and finacial affairs. I too have only read "Otranto" so can't say for sure if they were staples of this type of fiction, but if JA says so they must have been:))