Correct usage with compound nouns [closed]

Solution 1:

'Constable' is part of the title in example (3). Compare

• (She married a Captain George Walters) ... (Here is Captain George Walters)

whereas 'w/Witch' hasn't been elevated to title status ... there is no compounding involving 'witch':

• (She married a teacher, Geoff Warner) ... (Here is a/that teacher, Geoff Warner)

With Bishop/bishop (and indeed Constable/constable, as KillingTime points out), you can choose whether to use the title or the position.

Positions / classifications (... a teacher, Geoff Warner // ... a bishop, Harry Carey // ... a witch [or Witch, as per JKR], Hermione Granger) are here shown in appositive constructions, and will need a comma, and usually uncapitalised (Rowling may capitalise as a 'race', as Tolkien does with 'the Dwarves are a secretive folk'. Note his irregular spelling too (though this is not a quote).)