Could Sin Prodder's partner in crime, Dark Confidant, fit here?

It is certainly doable, in my experience Sin Prodder brings evasion and small Shocks that add typically add up to multiple Lightning Bolts worth of damage for more. It really depends on if you can afford that extra damage though. It is important to be mindful that the curve tops at 3cmc unless you count Gurmag Angler which is treated as 7cmc that can be quite large chunk of damage which is not considering how typically the deck sides in 5cmc Goblin Dark-Dwellers.

In short it is possible, just be aware of the cmc of your cards which can be quite damaging is all.

Now I'm seeing the difference. Well in that case, what about Tombstalker and/or Bedlam Reveler?

I've been playing around with a tweaked version of this and it seems really powerful. Tombstalker and Bedlam Reveler seem just as powerful as I thought. Forcing the opponent to let us keep these super discountable bombs is vicious. And it helps to fuel delve and Reveler's spell delve when the opponent elects to mill cheap spells reveals by Sin Prodder. Very powerful.