Hi Taka
I'd say the word "hot" is used similarly to the adjectives in your first sentence.
Distributive justice, absolute, rigid, and unvarying, must be observed by anyone who has children to deal with.
The words "absolute, rigid, and unvarying" modify "distributive justice".
Taka“There is no proof that Pekin Man knew how to light it, and it is unlikely that he had learned how to cook. If he had, he would not have had to crack the bones of his food animals to get at the marrow, which, hot, could have been scooped out with relative ease. ”
In that sentence, the word "which" refers back to the word "marrow", thus the word "hot" modifies "marrow".