US prisons have increased 10 times in the last 40 years for prisoners. Corporation have bidding wars for cheaper slave labor. Marijuana victims were the easiest pickings.

Possibly none because they are not resoureful. Most inmates are not from rich or uncomfortable families.

They will probably just hide behind the regulations the government passed, especially the ones giving corporations immunity. Few prisoners families will find funds to fight litigation - I'm sure it is very expensive to extract real evidence out of the prison system. Inmate testimony is naturally not trusted in court, guards how behind their union and protect their cushy jobs for life, and the corporations do what corporations do - maximizing profit.

But if you could sue a prison and win then why not sue the government too? They should be on the line for malfeasance and reckless endangerment.