Like I said, there are lawsuits and there should be, because a business is ultimately responsible for what it sold and who it chose to do business with to a fundamentally higher standard than an individual is.
The consumer facing businesses can turn around a sue their suppliers to continue the chain.
Finding they destroyed documentation that they knew something would indeed be a pretty big smoking gun. There's no real reason to think that they did though, since the businesses in question aren't actually making any money off of it or in a position to benefit. They actually loose money by having to pull stock and destroy it.
In at least one case, we know which company added the lead and which potentially knew about it, they're just in Ecuador.
Also, felony murder requires that you have intent to commit a criminal act. As written, not necessarily as applied, it would apply if you agreed to drive to a gas station robbery and your passenger killed someone. If you just agree to give someone a ride and then they kill someone you're not culpable, assuming you said "oh hell no" and then didn't continue to give them a ride post-murder.
True, but in the modern era so is aluminum, and I would have expected essentially everywhere to have updated by now since we're more than a century into knowing lead and food don't mix.