For the Film settings, in all honesty I would just go with the defaults. If you just want to hand them a CD of JPEG files without having to do any tweaking, this will give you the best results under the widest variety of conditions.
I've experimented with the other settings, and my opinion is that they're more for giving the photos a particular "look" rather than for trying to correct for different picture-taking conditions. In other words, after some disastrous experiments to the contrary, I now always start off with the default settings and alter them only if I've got some specific result in mind.
If I were you, I wouldn't even worry about the green filter -- suppose all the bridesmaids are wearing green dresses?
You can leave the white balance at auto for the flash as long as you're going to be shooting in b&w. If you change your mind and try color, I'd set it for the dominant light source, whether that be flash or ambient.
The problem you'll have shooting in color with flash if the ambient light is tungsten, is that the auto white balance will set the camera to match the tungsten lights; then, when the flash fires, the areas it fills will look very cold relative to the rest of the shot. If you set the white balance for flash, then the ambient-lit areas will look too warm, which is technically incorrect but much more acceptable to viewers!
An old trick that's worth trying is to get an amber color-conversion filter (a square plastic one is easiest to use for this) and put it over the flash unit; this turns the flash into a "tungsten-balanced" light so that the white balances will match.
"Never trust a graph without error bars."