There have been some hints as to the careers of WFRP fourth edition. When the pre-order was announced, it was accompanied by three images of different careers. Also on the covers released as the first teaser are four adventurers with iconic looks. That gives us sixteen careers so far.
From those images and that number I presume that the career structure of this edition will be much like first and second edition.
I haven’t seen the careers in the images identified anywhere, so my best guesses are found below using the careers from second edition as reference.