The split kick is demonstrated in the "moves" section of Single Player (that shows video demos of each of the lightsaber moves for each style).
To access it... start a game and then press TAB (default key) and check out "moves" for staff.
Note that these various spinning/split kicks and certain other moves are NOT available in MP (though I wouldn't be surprised that now that the tools are out some mod makers won't try to add them to MP).
As to cloaking with the Shadowtrooper (or the Imperial Saboteur) I don't know.
I know that in the 1.01 patch it was made so that if you were playing as Boba Fett Force Lightning becomes his flame thrower.
Perhaps using a certain force power activates the cloak... like maybe a level of Mind Trick?
The "Cloaking Shield" item is normally only available in MP, so it may be that cloaking is simply an AI only move. Dunno.