4). To
@MSSportsGuy's point about the sit out rule, I've wondered the same. My only guess is that the rule benefitted the schools in the past and they didn't care. Now that the waiver rules have tightened up, it's a different story as approvals have been a lot harder to get than before.
While I am old school, I find it terrible that a school could block a transfer to a certain program, or even make life miserable trying to get away from a bad situation. That doesn't mean the part about sitting out a year was bad and I believe it reduced tampering, allowed kids (because these are young people we are talking about) to give it thought before pulling the trigger and also let coaches be able to make longer term plans.
To me, sitting out a year wasn't punishment since the player received a scholarship, could practice and get the benefits of being on the team. They just didn't play in games and got the extra year back after the sit out period was up. I literally don't recall a transferring player ever getting a waiver for immediate eligibility approved in CFB, MBB, or WBB when I was younger but I haven't done any exhaustive search on the matter.
Immediate eligibility was done for the coaches and P5 programs, not for the benefit of the student. It gives teams immediate gratification. The gate will eventually come down on second transfers as well and then it's free agency.