Who was the least powerful member of the second triumvirate?

One could loosely say that Lepidus was the weakest member of the second triumvirate, but only because the other two, Antony and Octavian get the lion's share of the attention. Now, Lepidus had been one of Caesar's lieutenants and had administrative and military abilities, which were the reasons that Caesar chose him for his Master of the Horse. Even when he lost his power to Octavian, he was not exiled completely, but was sent to a luxurious country estate where he lived out his life and could be watched. This says that even though he was out of power, he still had a following.