Is this pokemons good to be the elite four: sceptile lv 67 : leaf blade..

NO it's not. Sceptile's fine everyone else sucks all your Pokemon need to be at lvl 55 or higher. Here's your necessities. Fight type move or Pokemon for 1st(dark elite) and 3rd(ice)elites. 2nd elite(ghost elite) I have an absol that knows shadow ball. Do this or use bannette. 4th elite(dragon elite) usean ice type move or pokemon. I recommend the move because ice type Pokemon are hard to train. And lastly the champion. He uses water tye Pokemon so have electric, grass, AND flying types. Grass for a wiscash, flying for ludicolo, and a strong electric type for every one else. Hope I helped : )

It looks like you've been training only Sceptile and Wailord and captured the rest on Victory Road.
You don't need to be atleast level 55, but you do need a team where the weakest Pokemon is atleast at level 45.
Wailord should have learnt Water Spout at Lv 44. Teach it Water Spout in place of Dive. Remove Blizzard for Ice Beam. Blizzard has terrible accuracy, so ice beam is better. Train Taillow! A level 21 taillow wont be able to take even 50 hp of Sidney's Shiftry(shich is weak to flying and is at a low level).
Let me give you the example of my team:
Swampert Lvl 53:surf, earthquake, ice beam, muddy water
Flygon lvl 53:dragon claw, faint attack(necessary for killing ghost/psychic Pokemon who use double team or any accuracy lowering attack), earthquake, fire blast
Magneton lvl 53:Thunder, thunderbolt, shockwave, zap cannon
Swellow lvl 53:Aerial Ace, fly, steel wing, wing attack
Heracross lvl 53:Endure, Reversal, Vital throw, Dynamicpunch
Ludicolo lvl 53:Hydro pump, sunny day(solarbeam attacks on first go), rain dance(this helps in setting up thunder to NEVER miss), solarbeam
With these Pokemon, I didnt even use one full restore or revive. Most of my kills were OHKOs.

They are heading the right way, but your going to get smashed by them try to get all your Pokemon up passed level 50 or more that's the only way you can win.