An enema is not part of the Master-Cleanse and is in fact greatly discouraged in the book at any time.
RE tea in am and pm - i don't have my book in front of me, but i am pretty sure it says tea in pm and swf or tea in am. the book really encourages the SWF (Salt-Water-Flush) so i read into it that you should try the swf first and alternate with tea when necessary.