Elite 1: Weak to fighting - LV 60 Blaziken + Breloom (Black belt, Sleep & Fighting move Kill) normally can 2HKO with focus punch/sky uppercut when foe sleep
Elite 2: Dark hero can kill, either Absol / Sharpedo / Mightyena / Shiftry @Lv60 bite/crunch can handle, sleep & switch for dark mons and kill
Elite 3: Same as elite 1
Elite 4: Rayquaza available in Emerald before Elite 4, catch it and outrage every mons (Dragon move supereffective to all foe mons here), switch out when confusion, and switch in back
Elite champion wallace:
Ampharos (Gyarados, wailmer, milotic, tentacruel)
Rayquaza (Ludicolo, whiscash)
If average lv 55, maximum need 20 revive + 20 Full restore + 30 hyper portion
Rayquaza has rest, use it wisely