I think I was wrong on Cossa's waiver exemption, he may have missed it by like a month since he turned 19 before the end of the year he was drafted, wow. Hopefully I was right but I don't think I was based on digging into it more. People seemed very confused by it so when I went to look at the rules again I noticed the "waiver age" clause:
If a player turns 18 between Jan. 1 and Sept. 15 in the entry-draft calendar year preceding the first season of the player’s entry-level contract, they are considered 18.
If a player turns 19 before Dec. 31 in the entry-draft calendar year preceding the first season of the player’s entry-level contract, they are considered 19.
November 21st birthday. Sheesh.