Additional Ironhand Gnomes

Ironhand Mining Village

I initially believed the Decrepit village was not an Ironhand village, but the dialogue from characters like Welso suggest every deep gnome in the area is an Ironhand gnome, including the executed and those who died from the cave-in.

This means they already lost at least 20 gnomes to this expedition, and the others assume the three taken to Moonrise probably won't make it out alive. This is where 20 gnomes comes from: 12 from the cave-in, 2 executed on the path to the Decrepit Village, 4 executed in the Decrepit Village, and Meerna and Wicky. Wicky died inside the cave-in while Meerna is killed by Nere no matter what you do.

Angleiron's Cellar/Baldur's Gate

There are a few additional guaranteed characters if everyone has made it back alive, and then stand-in characters (I have yet to meet them, I'm going to try in my current playthrough).

Hogi Nuners

Hogi is the default character at the cave's entrance who stops the player from entering, unless Wulbren was saved and is expecting you.

Bumpnagel

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Dulbers Frint

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