What is the expiation for backbiting the living and the dead, and would informing them lead to adverse consequences?

Restoring financial injustices is obligatory unless their owners or heirs pardon them. It is also obligatory to seek forgiveness for non-financial injustices, such as backbiting. If it is impossible to seek forgiveness from the wronged person due to their death or fear of causing problems, then it suffices to conceal the sin, repent, frequently seek forgiveness for the wronged person, supplicate for them, praise them, and for the repentant person to increase in good deeds.