Under the current requirements in Aus for fixed wing you'll need 1000hrs Ag, 100hrs on type (generally AT-802 or Turbine M18), experience in hilly terrain, as well as several other courses.
At this stage Ag is the path to a career as a water bombing pilot in SEATS in Aus but there maybe other avenues in the future. I can't see an operator putting someone in an AT-802 on fire work without an Ag back ground unless they had overseas fire experience, or a lot of experience in tail wheel aircraft, low level, in hilly terrain.