The Italian Islands are Sicily and Sardinia i guess, but Cagliari is the capital of Sardinia, so it should'nt be here... And i don't think Venice is on one of the isles...
Pyeongyang is a capital of Korea, just North Korea. While South Korea may claim the whole of the peninsula, in practical terms it does not control it, but it serves and is diplomatically recognised as the capital for the North.
For H countries, that is too technical. Either capitals are allowed or they aren't. What is your reasoning here - that since no city can be the capital of all the H countries, that means all capitals are allowed for this one item? Just disallow capitals and largest cities across the board so that people taking the quiz don't need to read your mind for one answer that has special but unknown rules.
Aberdeen, Dundee, Perth, Inverness and Stirling.