If Sakurai managed to disregard the fact that Wolf would be easy to make, is a nice promotion for new StarFox, is a unique StarFox character, and provides another villain, a unique type of villain (midweight) not in the game, to be exact, I have a hard time believing that he would continue to disregard Wolf after all the support Wolf seems to be getting in the Ballot. I think all these things combined he would finally put two and two (or... 6...) and decide to develop them.
Seriously, if Wolf is not being worked on already for pre-ballot, he would be a ballot choice.
I know for a solid fact SOMETHING is being worked on. Whether it is a ballot character that they want to release right as the ballot ends, or the last couple pre-ballots, I can tell you without a shadow of any doubt what-so-ever some character is being worked on.
Sakurai's team is not just gonna sit around for 4 months.