After reading this whole thread, my answer would be his biggest mistake is, at a minimum: ALL of the above!What was his biggest mistake?
What I've learned from experience is that it is NEVER just one (1) thing. It's a flurry of things. It's a bunch of random actions (some with consequences) that push the target, e.g., Tate, closer to an investigation, indictment, arrest, conviction, and subsequently being remanded to prison!
There is a phenomenon in the prison industrial complex around the world that has been lost on most people. The phenomenon is that there are NO mutes in prison.