Hum - might number 2 be considered witness tampering?
I don’t know - perhaps @ekat or another of the legal professionals can weigh in on that.
And I thought of a possible fourth motive - to try to get Tarshis to reveal that he had other information regarding the goings on at HH (because he surely knew more than what they learned through their illegal recordings), so they could try to “lead” him into revealing such information so they could formulate a plan to counter any such testimony at the upcoming trial.