The negotiations should not affect the timing of the referendum. If I remember correctly, the way the petition process works is that the petition must contain a certain percentage of voters' signatures. If they petition has the correct percentage, and it does, then the city council either votes to approve it, or they have to put it to a vote. The petitioners met their requirements and I believe the council did not approve it, so it goes to a vote. This should be placed on the ballot regardless of any other action involving the stadium.