That is a good idea. Unfortunately, it is currently not possible to "hide" certain pages of a guide to the public (note that with Web Publishing C, the _whole_ guide is "hidden").
That only refers to the content on the website. New pages do not affect apps and eBooks, because apps and eBooks only contain the pages that you sent to us in the Table of Contents.
For the website, it usually takes some weeks/months for Google to rank new pages at the appropriate position. Therefore, I would recommend entering the pages and the unfinished content as soon as possible - and then improve it over time.