Al-akhyār means distinguished righteous persons. The transmitted discussion includes prophets, angels, the righteous, and martyrs; the immediate issue is the reality of intercession, not a full ranking of every intercessor.
Prevention of punishment: a plea for pardon before punishment begins.
Relief or release: reduction of punishment or removal from it.
Higher ranks: asking that a righteous person's reward be increased.
These are different outcomes. The central dispute with the Muʿtazilah is intercession that averts or removes punishment from a sinful believer, rather than simply increasing a virtuous believer's reward.