So how does generating a one time pad from mutually accessible data fit into this scheme. Is the pad the cipher or the key?

If two people agreed that the pad would be the output of a particular pRNG given the 3rd paragraph of the second article on the third page of that day’s newspaper as a seed.

The attack vector would be shortcomings in the pRNG I guess? Which could result in the possibility of some sort of statistical language attack?

Or the attacker could guess the newspaper text & algorithm.