Not necessarily a straightforward connection, as none of the items being discussed have a direct revenue impact only indirect impact to brand value etc.

Knowing it is unhealthy for teenagers does not have direct negative impact on advertising revenues per se . It is perhaps feasible to argue that keeping this information under wraps without a legal requirement to disclose is the optimum management fiduciary thing to do to maximize shareholder value by avoiding bad press.

Of course there will be lawsuits around this as other things, but it is not all that clear

It does not need to impact revenue, just share price.

Yes, but that is inverse here after all. Only If they disclose this report the share price is going to go down.

Without a leak we would have never needed or gotten to know this report, so logically keeping it hidden/buried was the best course of action with regards to shareholder value ?

A valid suit maybe about their poor security/ control processes for their Workplace tools that lead this leak.

Shareholders could perhaps sue saying they should not fund such research/ buried it well etc, not sure a court/judge would look nicely on a such a suit.