Iago—Vice or Devil?

Summary

For a considerable time critics have traced the characteristics displayed by Iago back to the Vice, the artful seducer of the Morality plays. Alois Brandl in 1898 included Iago among the descendants of the Vice, although apparently associating that figure with the Devil:

If we follow the role of Vice in the other English tragedies of this period and the following decades, we still find Haphazard in ‘Appius and Virginia’ as well as Ambidexter in ‘Cambyses’ as representatives of the old Morality-type, i.e. as seducer and hypocrite. In Marlowe's Mephistopheles the original diabolic character of this figure once more reaches full expression; in Marlow's black Ithimor, Shakepeares's Aaron and Iago is it still strongly to be felt;

and Cushman in 1900, while showing the utter disparity between the nature of Vice and Devil, explicitly endorses Brandl’s derivation of Iago from the former and would add other Shakespearean villains to the list:

Why not also add to these Edmund in Lear, Richard III, Don John in Much Ado About Nothing and Antonio in The Tempest?