You misunderstand the map, Ferrara was a part of the Donation of Pepin, making it
de jure a subject of the Papacy, but as you said the e'Este ruled it with virtual independence, though they were in reality under Venetian and Milanese influence. As I said, everything in the map on the right not in yellow was
de jure subject to the Pope, but not
de facto.
Here's the holdings of the Apulian branch of the Orsini family in 1459 (the Princes of Taranto), its the closest I have to one of 1453.
View attachment 614740
(From
I domini del principe di Taranto in età orsiniana (1399-1463). Geografie e linguaggi politici alla fine del Medioevo by Francesco Somaini)
There were many other large fiefdoms in the Kingdom of Naples at the time though.
Venice 1454-1455 (ignore the lighter shaded portions, except with reference to borders of the polities, they are "it merely shows the Venetian "sphere of influence" as seen by Venice)
Milan 1454-1455 (same principle for the lighter shades as above)
Also Castiglione della Pescaia was part of the Crown of Aragon.
Apologies for the map spam everyone.