My thanks also to Midwest Mom, great post. We too benefitted greatly from HSBBW, both from individuals giving advice in PMs, and from the many threads on recruiting. The advice here has been so helpful to us.
Ironically, the item of yours that I agree with the most is #7, no one else’s journey is the same as your son's! My son's high school coach did not do much but the travel coaches did, he went to Headfirst only in August before senior year, he did not cast the right net early on. We did not have a coherent plan, it was more of reacting to events as they happened. The travel organization head was good, and contacted coaches when we asked, but he never explained how the process worked, just said things like "he needs to get his 60 time down," without explaining why or how much, and he didn't have much of a sense of HA D3; we would not have gone to Headfirst if I hadn't read about it here. My son didn't really know what he wanted out of a school until after he had visited them (which was after he had offers). Maybe if we had done things differently, the outcome would have been different, but there was an outcome, and along the way there were a lot of great baseball experiences. I feel that I didn't really understand the big recruiting picture until after it was done - and that was with extensive (obsessive?) reading on HSBBW and keepplayingbaseball.com.
Because both the recruiting timetable on HSBBW, and the useful one on keepplayingbaseball, are pretty vague; they say, freshman year do this, sophomore year play here, do a showcase there, contact coaches there, when your time comes it will come. But, nothing I read came out and said the very basic thing, it all starts with your measurables. If we had known that sooner, the outcome would probably have been the same, but we might have had a clearer path.
What no-one has yet said, I think, is to enjoy it all. My son just loves playing baseball. He loved high school, even though each season had its disappointments. He loved summer teams and the challenge of high-level opponents. He loved fall ball, which in our area was very low-key, played with high-school teammates and other kids from the surrounding area. He loved playing with a local low-level travel team, on weekends when he had no other commitments. He loves wiffle-ball on the beach with his brothers. The recruiting part of this was a confusing and crazy ride, but the baseball part was always good!