It's hard to follow the rules with all these changes in Ballon d'Or, but, if I found the correct information, only journalists from all over the world vote. Last year 176 journalists voted.
Then there is FIFA player of the year award, where captains and managers of NTs vote. It's not as it was before when the journalists and the men in football voted together for the same award.
It will indeed depend on the result of the final, but in an unlikely case Croatia wins the WC, Modric will be a serious candidate. He's well known around the world due to playing for Madrid, and he's admired by all the players, coaches and journalists.
You never know with this award. People might finally be sick of the Ronaldo/Messi dominance that they could simply vote for someone who decides the final.