All firing that requires range guessing by the player must be declared before the resolution of any missile fire. This is done so that the player does not gain any benefit from measurements made to resolve other missile fire hits.

1. Designate targets, one at a time, and determine range.

2. Determine damage and remove casualties.

3. Test for panic any unit taking 25%+ casualties.

Yes.

You cannot shoot at the wood because you do not know that there are enemy within, and if you could see the enemy the weapons would not set the woods on fire.

Warhammer Fantasy Battle (unlike 40K) has no targeting restrictions based upon how close the enemy is. If a unit has unrestricted view of the enemy, the enemy is within the 90 degree fire arc and it is within range, they can shoot it.

No, except for the war hydra.

No.

House Rule: It is suggested that hits on figures in the first 2 ranks of hand-to-hand combat be randomized between the units engaged in hand-to-hand combat. This would prevent surgical placement of breath templates to wipe out units engaged in hand-to-hand combat.

No, all models get 1 missile attack. The number of attacks listed as a characteristic is the number of attacks in hand-to-hand combat.

The rules about having more than 1 wound are used to determine if a mount is considered a monster mount or a steed. Therefore, there is no +1 missile fire bonus for shooting at harpies, beastmen and unicorns.

Only war machines with walls to protect the crew gain the additional -1 to hit modifier (such as the Dwarf Organ Gun).

Yes. The only combination that is not cumulative is (character & skirmish formation) and (soft cover & hard cover). Combinations of (character & soft cover), (character & hard cover), (skirmish & soft cover), (skirmish & hard cover) are valid cumulative to hit modifiers.

+1 to hit due to large sized model.

Note that the -1 to hit modifier only applies when shooting at single man-sized character model. Therefore the to hit modifier is +1. This means that shooting at a character on a horse would count a 0 to hit modifier (larger than man-sized, but not a large target).