Fifteen fifty is the entry set and is reachable in a weekend. Eighteen fifty is the weapon, which is the single biggest power jump available to a PvP character and the reason most of these orders exist. Two thousand is the shoulders. Twenty two hundred is the title and the mount, and it is a season rather than a weekend. The cards are named for the reward because that is what you are buying; the rating is how the game stores it.
Self-play puts you in the team with two boosters, which means you are on the rating and in the games. Account share means a full team plays your character while you do something else, which climbs faster. Either way the rating is earned in real games against real teams: there is no queue manipulation on offer here, because win trading is what gets a team’s rating stripped at the end of a season.