Din's posts confirm that fortresses also follow the three laws of real estate: location, location, location!
I had a quick readthrough and it looks possible to put together a list of Venetian regiments in the Morea and Dalmatia in 1715 from Prelli/Mougnai, Favaloro and Tra I Borboni E Gli Asburgo, if it's any help.
Aris K.