the difference between bump and normal other than bump being monochrome and normal being colour is the efficiency of calculation

normals maps are basically just bump maps but they have been through the step of calculating the angle of the normal. this preprocessing stage saves on valuable calculation time and thus makes it a better alternative to bump mapping in GAMES

why you would use it for a movie... hmm... that's actually a good one, you would use it, to be easy on your computer so it doesn't have to do so much if it were all just polygons

you can use displacement maps. those are monochrome maps but they actually raise the surface. it's not an illusion like normal and bump maps. displacement maps take a lot more effort to use (i've yet to use one without it distorting either the model or the colour of the model), but are worth it if you get right.

you can make displacement maps from zbrush too

technically, since a movie is prerendered you can go all out on the polycount, provided the computer can handle it.
since your objects aren't animated i don't see why a high concentration of polys would be a problem. sculpt something in zbrush, import the high res mesh into maya, and you'll probably be almost done... although, Maya, being a truely 3D program wont take as kindly to a 10 million polygon mesh as zbrush can. (zbrush isn't a 3D program, it's a 2.5D program)
so yeah, you will want normal and displacement maps, if you want something to the detail of those reference pictures you posted earlier

also, since you are rendering for a movie you'll be prerendering scenes and compositing your live footage with it. it would be best for you to learn about render layers (or render passes as they should be called i think?)