hussie wasn't paid 20k to draw the two trolls getting killed. two people pledged 10k each, the reward for which was your character becoming a canon character in homestuck; however, they failed to fulfill their pledge, so they were drawn... and killed right after, iirc
10,000 guaranteed the characters survived one panel
A 100,000 pledge guaranteed more than one.
So yes, he was paid. I know the wording on the wiki is confusing.
I got in contact with some peeps at the wiki and they changed the sentence so hopefully that’ll help clear up any confusion on the topic.