MUSKEGON — A deal to redevelop the former Ameribank building is making headway, but the project remains contingent on incentives from the city and the Michigan Economic Development Corp. Muskegon developer John Essex, managing partner and president of Core Development LLC, submitted a formal purchase agreement to the city prior to the Jan. 30 deadline. If the project goes ahead, it would transform a partially demolished building into a new use in the core of the city’s downtown.