How long should I wait for the response of the possible postdoc advisor?
I don't think there is any need at all to communicate further with this PI regarding this matter.


I don't see any point in asking him if he "likes" your CV.  It's a weird request - it's not his job to evaluate your record at your request, or to tell you whether your CV is well-written.  If that is meant to be a way of asking him "What are my chances of getting a postdoc with you?", don't: that's not something he can reasonably evaluate until there is actually a position and he can compare your application with those of all other applicants.  
I would not write him back at all, regarding the postdoc specifically.
He doesn't have a position open, so there isn't any action he can take for you in the short term.  If a position appears at some future date, and if he is still interested in you as a candidate: well, he knows how to reach you.  And sometimes "Please send me your CV and I will keep you in mind for a future opening" is a polite way of saying "No."
Definitely do not contact his other postdocs.  The hiring decision is for the PI to make, not the postdocs, so any questions about it should be directed to the PI.  Trying to go behind his back to wheedle out inside information from them would be unprofessional, will annoy the postdocs, and will probably destroy your chances of ever getting hired if the PI should learn of it.


If you have some other bona fide reason to stay in contact with this PI (discussion about research topics of mutual interest, questions about his papers, etc), that could be helpful in keeping yourself in his thoughts for possible future postdoc hiring, as well as general networking.  But they had better be for real - if you come across as making up reasons to contact him just to get his attention, that will seem slimy.