So one route for you to consider is walking on. Columbia gets 8 recruits per year (due, I'm told, to having no men's lacrosse team), most of the other Ivies have 7 most years (can be lower). Anyway, that means there are players on most teams who got in as regular students and tried out and made the baseball team. I know two current Ivy players who made a roster that way (warning: they got almost no ABs last year). The coach might even say around this time frame, "If you can get in we have a roster spot for you" (I know an uncommitted 2019 who heard that recently from an Ivy which already has 7 commits). With your grades, SAT, and at Columbia legacy status, that might be a viable path for you, without doing a PG year.