What happens when the feat Born of the Three Thunders modifies thunderhead?

The feat Born of the Three Thunders (CAr 76) reads, in part,

When you cast a spell with either the electricity descriptor or the sonic descriptor that deals hit point damage, you can declare that spell to be a spell of the three thunders, with half its damage dealt as electricity damage and half dealt as sonic damage. In addition, the spell concludes with a mighty thunderclap that stuns all creatures that take damage from the spell for 1 round unless they succeed on a Fortitude save, then knocks stunned creatures prone unless they succeed on a Reflex save (both saves at the same DC as the base spell).

It’s clear the feat is intended to work on instantaneous spells, but a few electricity spells and sonic spells that inflict damage have durations other than instantaneous. The one I’m interested in is the 1st-level Sor/Wiz spell thunderhead [evoc] (SpC 219), which has the electricity descriptor, has a 1-round-per-level duration, and says that it

creates a small thundercloud over the subject’s head. The cloud moves with the subject, following it unerringly even if he becomes invisible or leaves the region. In every round of the spell’s duration, a miniature bolt of lightning leaps from the thundercloud to strike the subject. Each bolt deals 1 point of electricity damage that is negated by a successful Reflex save.

Here’re the questions:

  1. Which of the following is true: When the miniature lightning bolts from spell thunderhead, when modified by the feat Born of the Three Thunders, strike a foe…
    • only the first miniature lightning bolt will trigger the effects of the feat Born of the Three Thunders.
    • each miniature lightning bolt will trigger the effects of the feat Born of the Three Thunders.
  2. Which of the following is true: At least one miniature lightning bolt from spell thunderhead, when modified by the feat Born of the Three Thunders, will…
    • have an equal chance (a coin toss) of inflicting either 1 point of electricity damage or point of sonic damage.
    • inflict 1 point of electricity damage and 1 point of sonic damage (because even if halved minimum damage is 1).
    • inflict 0 points of damage (because half of 1 rounded down is 0).

Note: There’s probably an argument that says the spell thunderhead, when modified by the feat Born of the Three Thunders, doesn’t do anything as the miniature lightning bolts inflict the damage and those come from the thundercloud which is created by the spell, and the thundercloud does no damage. I’d rather not entertain that possibility as it gets into the differences between the conjuration and evocation schools of magic. To avoid such arguments, assume that the feat Born of the Three Thunders actually has an effect when applied to the spell thunderhead. Thanks.

“Who Cares?”
A buddy wants to play an electricity-chucking dude. And while dragonfire adept and warlock are interesting, a wizard with the feat Storm Bolt (CM 47) serves this purpose, too, and is… um… a wizard. So, yeah. In looking for ways to make electricity better, the feat Born of the Three Thunders makes electricity attacks more versatile, which is awesome. The feat Mark of the Dauntless (Dra 142) later, and the Wiz6 can do pretty well, shocking folks all day long if he keeps at least 1 Born of the Three Thunders lightning bolt prepared. The thunderhead thing arose because I wanted an interesting 1st-level electricity spell that could be Born of the Three Thunders. (By the way, I know the Storm Bolt feat and the Born of the Three Thunders feat don’t interact. It’s just a theme thing.)