With my experience with terranim8or, I would normally hide or drop everything not needed in the scene, just the objects that you want to have particles attached to them left in (terranim8or really does not like figs and will not load them)
Then when you have the particles set with their corresponding targets, save it out and reveal or reload the missing objects......I had terranim8or running non stop once for 2 whole days loading a scene without success, so finally gave up on loading in full scenes and now use this stripped down method ......
I usually plan where the particles, fire , explosion will be and use terranim8or to place all those effects before any major additions.