Tyranitar: Should probably be top of your list unless you already have good B/C and B/SE TTars. TTars are very useful for raids.
Dragonite: Also a great target, but probably not as immediately important as Tyranitar, IMO. Should be done eventually.
Alakazam: I personally would not Fast TM him. Confusion is a fine move. At least I would wait until I have no more good Fast TM targets.
Charizard: Would be more of a pet project, IMO, not something that is terribly important to do.
Flareon: I would probably rather evolve a few high level Eevees and hope to get a FS/OH Flareon. Just to save dust.