Triangles in games remain triangles, the polygons get optimized so they may use as much texture space as posible and have good looking shapes that may get correctly animated afterwards and keep the polycount low, so, it is best to work in triangle meshes than polygonal ones. still, 3300 triangles is a nice amount.
ZBrush is used for the normal maps generation and painting.
Probably the meshes are done in MAYA or Softimage, then, they get exported to ZBrush, and they are finely detailed there and painted, then, the textures are generated and baked into the lowpoly models, and these are rigged and exported to the game engine. It is the most common workflow.