Re: Writing Leonard Nimoy
You might be able to connect to him through whoever published his most recent book. If you're a member of IMDB Pro, you might be able to see the name of his agent. And another way to connect is if a magazine has run a lengthy article on him, you could try going through them. Decades ago, Time Magazine did a cover story on Woody Allen. I wrote him a fan letter in care of Time, and a few weeks later got a note back from him answering one of my questions.
Dr. Howard, Dr. Fine, Dr. Howard: For duty and humanity! --Men in Black (1934)