No Page rank- If your website is old and you have page rank few days ago then you may be under some kind of penalization. For new website there is no problem because there may not be pr allocation to that project. PR-0 means PR-0...........nothing else.
PR and indexing have got nothing to do with each other. pr0 is better than n/a since it has got some value as against compared with n/a
Yes its different i think. Since the first site launching its N/A and some time if google has recognise our blog existence its will go PR 0 or some maybe jump to 2,3,4 maybe .. but i don't know the different impact of PR N/A and 0 to serp? or its both doen't have impact?