Sorry iNom you cant just say nobody else answer ;) unless your Mike and your answer clearly willl be the best, unfortunatley we are not Mike.
Anyway SlipperyDevil this is a certainly intresting team but there will be replacments and its nice to see Scizor being used, though I will pick up on your beloved scarf set very soon.
Scizor
316 Speed will outspeed most of Ubers but you aint gaining anything IMO your just loosing possible Atk.
You need to build different sets for each tier and this set isnt cutting it for me, the only advantages I can see is U-turn and Superpower possibly going first, allot of ubers is scarfed.
So now we have a Pokemon with an item which is basicly locking it into one move?
So I recomend this set highly
Scizor (F) @ Choice Band
Trait: Technicion
EVs: 248 HP / 252 Atk / 8 Speed
Adamant nature (+Atk, -SAtk)
-Bullet Punch
-U-Turn
-Superpower
-Pursuit
I used this exact set once and it was very good.
It has the skills to revenge kill very well and the strongest U-turn in the game which will do very good damage to anything not resisting it.
Superpower is very good for countering Pokemon like Dialga (fingures crossed is locked in to Dragon Pulse).
it is also very good at damaging Pokemon on the switch ins.
Now pursuit will be a very usefull move trapping in Pokemon that are locked in choice or countering mewtwo stupidly not running Flamethrower.
With this set you will hit like a truck but becarefull, Scizor is very easy to counter in ubers.
Creselia
As much as it hurts me to tell you this but Creselia is not Ubers fit, it is just a way of setting up boosts and hazards while you hopelessly spam Protect away.
Also your team lacks hazards and hazards will be what determines most games in Ubers so you may as well use Ferrothorn
Ferrothorn (M) @ Leftovers
Trait: Iron Barbs
EVs: 252 HP / 48 Atk / 208 SDef
IVs: 31 HP / 31 Atk / 31 Def / 31 SAtk / 31 SDef / 0 Speed
Sassy Nature (+SDef, -Speed)
-Gyro Ball
-Power Whip
-Spikes
-Stealth Rock
Though you do currently have a Ho-oh problem that cant be solved without changing your whole team, anyway you have plenty of quik Pokemon to counter it.
Either way welcome one of the best Kyogre counters there is.
Brilliant typing, Great defences and the ability to set up freely, what more could you want.
Also a great Pokemon to switch into a locked Outrage user as not only does he resist it but he damages them with the spikes.
Stealth rock is needed on almost all Ubers teams and Spikes is there to finish them off.
You could alternativly use Forretress with spinning abilities but you have not got any Pokemon capable of taking small damage from Kyogre and Forretress certainly doesnt.
Also Ferrtohron has the ability to do decent damage to Deoxys-S with Gyro Ball.
rayquaza
Roost? Rayquaza may seem bulky for tiers such as Ou but not Ubers.
rayquaza is ment to be used as an all out attacker.
Rayquaza @ Choice Scarf
Trait: Air Lock
EVs: 252 Atk / 4 SAtk / 252 Speed
Naughty Nature (+Atk, -SDef)
-V-create
-Outrage
-Extreme Speed
-Earthquake/Draco Meteror
Mew can tell you the successfullness of this set.
Mewtwo
Timid Nature over Modest, Aura Sphere over Focus Blast and Flamethrower over Shadow Ball.
But Flamethrower over Shadow Ball is just my opinion.
Be sure to try it out but Darkrai does the exact job and means you loose a needed fire slot.
It may hit Giritina when needed but most carry Shadow Sneak which will hit Mewtwo very hard possibly being a ko after hazards.
Finally Thunderbolt wont be hitting Kyogre as hard as Thunder will which is mainly why its there but it will hit Lugia without weather.
Darkrai
I remember using this set when I used ar years ago but this is not how Darkrai is ment to be used.
it is very gimmicky and must be totally rethought, if you want my logic behind just comment my fingures are hurting :D
Darkrai @ Focus Sash
Trait: Bad Dreams
EVs: 4 HP / 252 SAtk / 252 Speed
Timid Nature (+Speed, -Atk)
-Dark Void
-Dark Pulse
-Focus Blast/Hidden Power Fight
-Nasty Plot
I cant stress how bloody annoying this friggin set is, I never use Darkrai I find it noobish but this set tics me more than any other.
They all tend to carry the same moves but Focus Sash....
The amount of times I had lost my Deoxys-A to a 1 hp Darkrai is to much to think about for me :'(
Arceus-Steel
Scarfed Ho-oH can currently tickle this team to death so I'm just going to chnge the type.
Arceus-N
Arceus-Normal @ Life Orb
Trait: Multiply
EVs: 88 HP / 252 Atk / 168 Speed
Adamant Nature (+Atk, -SAtk)
-Extreme Speed
-Swords Dance
-Earthquake
-Shadow Claw
Okay standard extreme killer set, 1 swords dance and you will sweep there team with extreme speed.
Shadow Claw will deal with pesky giritinas butr should only be used when they have little health, Giritina is the bulkiest Pokemon in Ubers IMO.
Finally I'm finished, apoligies again to Gt who sounded pretty desprate to answer, feel free to answer any way.
I highly recomend you take all of this advice though I have become very experienced in Ubers recently and have been using ubers since early may possibly earlyer.
I love Ubers :D