As I don't know the 'apo sandawa story' well, I can't say for sure who the main characters are. But I assume Apo Sandawa is one of the main characters.
Well, without more context, it's difficult to say precisely. 'St cloud times' could be a reference to a publication perhaps, like a newspaper from St. Cloud. And 'apo mapping story' might be about a mapping project. Maybe it's a story about how some area in or around St. Cloud was mapped using a particular method or technology that has something to do with 'apo'. However, this is all just speculation.
I don't really know the significance since I don't know the details of this'st cloud times apo mapping story'. It could be significant to the local community in St. Cloud if it's about mapping their area for development or conservation purposes.
I'm not entirely sure specifically what 'dxd adult fanfic' is. 'DxD' might refer to a particular series (such as 'High School DxD'), and 'fanfic' stands for fan fiction. However, the 'adult' part implies it could be fan - created stories with mature or inappropriate content which is not suitable to discuss in detail.
The number of DxD novels can be a bit tricky to pin down. Different regions might have different releases and editions. Your best bet is to do a comprehensive search on popular book databases or consult with avid fans of the series.
The Highschool DxD manga has indeed finished. It wrapped up after completing all the planned story arcs and providing a satisfying conclusion for the readers.