Going to N with the engine idling while stopped at the lights will use less fuel than keeping it in D. This is a generally accepted fact. I've measured it on the Honda Jazz CVT with a Scangauge. Unfortunately Scangauge doesn't work on the Latio :-(.
Coasting to lights in N? It depends. If you need to stop quickly, keep the car in D. The fuel injectors will cut off (in the CVT anyway) until the car slows below 18km/h. After that, the torque converter unlocks and the engine receives fuel to avoid stalling. If you are quite far from the lights, you will probably gain some fuel savings by coasting in N. If you have your tyres inflated to higher pressures, you can coast for a fairly long distance. You can probably coast a good 400m on level ground and drop your speed from 50km/h to ~40km/h.
Automatic transmissions do have clutches. When you shift to N, the forward drive clutch opens so that no power is transferred from the torque converter to the drive pulley. The Latio CVT has a planetary gear shaft to perform reverse. Engaging reverse activates another set of clutches. I think the 2008 version of the Latio has automatic Neutral. So the 10-15 mode for the face lifted version is 19.4km/L instead of 18.2km/L. It also has improved torque converter lockup at lower speeds and runs the alternator only when it is efficient to do so. It also has the all important FC meter!!
I turn off the engine at long traffic lights. I don't think the battery needs to put out a lot of energy to crank a warmed up, well lubricated engine. It starts very fast.
If you are careful and have a good route, the Latio CVT can beat the Japanese 10-15 mode fuel consumption figures. I got 22.12km/L for my last tank of petrol. This does not happen all the time... That's 2km/L short of the Jazz's 10-15 mode number.
