Diablo Game Questions Blessed Hammer w/ Guard of Johanna: what Rune?

I can't seem to find a very recent answer on this and am left wondering if the older ones are still relevant.

I'm curious about what exactly gets boosted through the legendary power on Guard of Johanna.

For those who don't remember here's the legendary affix:

Blessed Hammer damage is increased by 200–250% for the first 3 enemies it hits.

So... what specifically does it increase the damage of?

If I'm using no runes at all or Dominion (hammers orbit caster), I'm gonna assume it's the obvious: first three enemies it comes across will take 200-250% extra damage from it.

But what of the other bonuses?

  • If I throw a hammer that hits only one enemy with Burning Wrath on (25% chance to drop fire AoE on hit), will that enemy standing in the fire effect proc take extra damage from it? What about another enemy that walks into the fire?

  • If my Thunderstruck hammer (lightning arcs between hammers and caster) hits no enemies, will it do extra damage on the first three enemies struck by the lightning arcs?

  • Will a secondary hammer spawned by Limitless (50% chance to spawn a new hammer on hit, once per cast) hit the enemy they spawn from with extra damage? Can they do extra damage from the legendary affix at all?

  • And finally, will the explosion from a Brute Force hammer deal extra damage to enemies as well?

Naturally all of these are assuming the hammer cast has not already struck 3 enemies before the other effects activate.

I'm split between choosing Thunderstruck and Limitless for my Blessed Hammer rune. Thunderstruck should add up to much more damage, especially in AoE situations, but depending on what benefits from Guard of Johanna's legendary power Limitless could potentially be more powerful against bosses that are fought alone.