Some of them are not there (e.g. Meta, Shell, St) because they are considered "private". Read more here on how to import them: http://mathematicalcoffee.blogspot.ca/2012/09/developing-gnome-shell-extensions_6.html?m=1
St Lib would really (!!!) help in writing apps with custom interfaces due to the use of CSS. If we could use the library with Clutter and gjs it would really attract developers due the easy of use of St and Shell libraries.