1) What is the rule regarding whether iterative attacks can gain the benefit of sneak attack damage? I'd prefer cites if possible,
SRD said:Sneak Attack: If a rogue can catch an opponent when he is unable to defend himself effectively from her attack, she can strike a vital spot for extra damage. The rogue’s attack deals extra damage any time her target would be denied a Dexterity bonus to AC (whether the target actually has a Dexterity bonus or not), or when the rogue flanks her target. This extra damage is 1d6 at 1st level, and it increases by 1d6 every two rogue levels thereafter. Should the rogue score a critical hit with a sneak attack, this extra damage is not multiplied.
2) Same question for scout skirmish damage and ninja sudden strike damage.
3) Are there any other SA variants?
A number of abilities in the game alow a creature to deal extra damage by striking a vital area. This category of abilities includes sneak attack and other abilities that work like it, such as a ninja's sudden strike and scout's skirmish. . .
Precision damage applies on any attack that meets the requirements of the ability that grants the damage. This includes multiple attacks made during a full attack. If conditions somehow change between multiple attacks, attacks that no longer meet the ability's requirmeents can't deal prrecision damage. . . .
A form of attack that enables an attacker to make multiple attacks during an action other than a full-round action, such as the Many shot feat (standard action) or a quickened scorching ray (swift action) allows precision damage to be applied only to the first attack in the group.
Cool. Essentially, the only thing likely to change the circumstances significantly is the ending of an invisibility effect as a result of making the first of the iterative attacks.
Or blind them.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.