What good would it do to replace the pin if the wood is sticking?
He was talking about the use of graphite being a problem on center pins, because of its tendency to gum up the contact area between the pin and its bushing. Over time you may find this part starts to exhibit friction and not function properly.
My four questions are still unanswered.
Experience has informed many technicians that a squeak is often not what you think it is, and the proper diagnosis and treatment ought to be performed by a knowledgeable tech, in-person. I suspect your questions going unanswered reflects this, and is not helped by your sense of entitlement.
One wouldn't think a squeak couldn't be dealt with without expensive service call.
One might be wrong. One might cause an even more expensive service call by self-diagnosis and treatment. But some people are very adept and figuring things out themselves. Before I got into piano work, I fixed something successfully and thought "hey, that wasn't so bad," and then I fixed something else and ended up tarnishing my bass strings. Live and learn.
It's your piano, you certainly have every right to treat it however you want. However, please don't blame technicians for not providing free advice, when they don't believe it can be properly given remotely.