Fewer publications hinder postdoc opportunities?
In my opinion, publications should not affect if you have sufficient experience and skills in the research project you are applying to and research field of the group you wish to join. Hiring postdoc researchers usually involves discussions with the professor who is hiring the postdoc researcher and probably a hiring committee at the institution. Therefore I think you may have the chance to describe your research activities and skills. You can also talk about your papers which are under preparation and those submitted and under review.
Therefore, as far as you can discuss your background and experience with your future mentor, I do not see any reason to be worried about part of your research publication which still need time to be published. People being responsible in hiring you, will see a package of your skills, experience, quality of your studies and many other factors and these can help increase your chances of finding a good postdoc position.