In answer to the second question,

The Latest News includelet is similar to the Filtered Item List, but is "hard wired" to only show a list of pages of type News. There's no particular advantage to using this includelet, other than the convenience of not having to configure the Filtered Item List.

It won't show anything at all if you don't have any News pages elsewhere on your site, which may be what's causing confusion.

Generally speaking, you can put any includelet in any column and it'll appear as appropriate! An easy test is to use the Custom includelet which just lets you add any content that you like, and place it in different columns to see what happens.

As with all CMS pages, you can Preview the changes before you put them live.

Thanks

Joe