character deck and tempest

Somewhat related, I know it's been asked before but haven't found an answer anywhere, do potential level tiers change with Tempest too? Like would level 61+ items become 3rd tier instead of 71+ or are they unaffected?

They do not. The only thing affected by the level changes were the job advancements for all classes except for KoCs, Evans and I'd assume Dual Blades too.