Ubers (Hyper?) Offense

This is my first time making one of these. I've played some for fun but I threw these pokemon together somewhat randomly and tweaked EV's and movesets to where I liked it. So far I have low 1800's rating, with 51 wins and 16 losses. A bout an equal number of each was hax/accidental OU team (both sides) so percentage is pretty accurate I believe.

Deoxys-Attack @ Life Orb
Trait: Pressure
EVs: 236 Spd / 88 SAtk / 184 Atk
Lonely Nature
- ExtremeSpeed
- Psycho Boost
- Ice Beam
- Superpower

Main attacker. EV'd to do more damage with physical than special. I felt I had enough special and Dialga's tend to give my other mons problems. Ran calcs on the drop in special power and I didn't appear to lose any OHKO's or 2HKO's that I would sorely miss. Mostly a revenge killer role. NOTE: Have not tried new EV and nature spread; used to be +spe with the EV's in the attacks basically flipped.

Rayquaza @ Life Orb
Trait: Air Lock
EVs: 36 SAtk / 252 Atk / 222 Spd
Hasty Nature
- Draco Meteor
- Outrage
- V-create
- ExtremeSpeed

Helps against weather reliant teams. Been saved a few times on thunders. Not used too much. Was thinking about using another dragon, maybe Latios for added speed. ES has saved my hide a few times, and helps to alleviate all of the debuffs I get. Reduced the Speed to 1 higher than the next uber on the speed chart to have more power, haven't tested. Used to be 4/252/252.

Mewtwo @ Life Orb
Trait: Pressure
EVs: 252 Spd / 252 SAtk / 4 Def
Timid Nature
- Aura Sphere
- Recover
- Psystrike
- Ice Beam

Standard attacker. Not much to say here. Auras Sphere puts decent dents in Arceus and Dialga. Not really having a chance to use recover, but not having much of a chance to use calm mind either. Hoping for input on a move to replace recover with, maybe substitute.

Arceus (Arceus-???) @ Iron Plate
Trait: Multitype
EVs: 236 Spd / 92 HP / 176 SAtk / 4 Def
Modest Nature
- Focus Blast/Thunderbolt
- Ice Beam
- Fire Blast
- Stealth Rock/Substitute

The real interesting set on my team. Steel for the resistances, select coverage move and be impressed. So out of left field it has won me many games. The team is somewhat built around him, as it is fun to use. However I am interested in opinions as to how it could be changed.

I had max speed, some more health, and some less special attack before adjusting it. I added modest and added special attack from hp and speed (checked the speed tier and didn't see any threats I was beating or didn't mind losing to, and reduced HP to 404 because it isn't there to take a lot of hits). Defense add is to give Genesect a special attack boost as most only get a chance to U-Turn me in a game.

I want help on the coverage moves. I was using thunderbolt but I feel its coverage got fairly redundant. Meanwhile Normal Arceus was rampaging on me a lot. So I added focus blast instead. I do less damage to Kyogre and Waterceus but I wasn't doing much anyways. I also lacked SR and some key KO's so I added it over substitute as I outspeed many switch ins anyways.

Palkia @ Choice Scarf
Trait: Pressure
EVs: 252 SAtk / 252 Spd / 4 HP
Timid Nature
- Spacial Rend
- Surf
- Fire Blast
- Thunder

Standard revenge killer. Max speed necessary for CS Genesect. Thunder to abuse the ever present rain, fire blast for the quad fire weaknesses. Fairly certain it is needed over flamethrower to kill Ferry in the rain. Spacial rend for the STAB, coverage, and the increased CH chance that has saved me.

Darkrai @ Focus Sash
Trait: Bad Dreams
EVs: 252 Spd / 252 SAtk / 4 Def
Timid Nature
- Dark Pulse
- Dark Void
- Nasty Plot
- Focus Blast

Normal lead pokemon. If slower than me, sleep. If faster than me... sleep. Dark Pulse 100% of the time against deoxys (cant risk mispredicting; me being asleep or used turn is much worse than them getting up SR) leads. If I see Genesect I send in Palkia. Darkrai I send Mewtwo but I would like help defending against this lead as well. Maybe lum berry on one of the attackers? After running damage calcs of course.

I feel I need help with SD Arceus. One of the most common pokemon and I only have the idea of Aura sphere with Mewtwo on SD, then extreme speed with Deoxys on death, or maybe survive a hit with Steelceus and hit twice with Focus miss. Suggestions on that front would be SUPER.

So yeah that's my team. As I stated I had about a 75% win percentage so it did fairly well. Some of the losses were misplays by me that I could have won, but surely some wins were that too. And as usual, as this is my first one, don't be too harsh on me about format and lack of pictures/humor :-)

EDIT: The speeds did not factor in pokemon not on the speed tier article here on Smogon. The base 90's were covered and Genesect was covered but if you can think of any missing pokemon be it Uber or not post that too!

I would change your Steeleus to a Physically Defensive Ghost Arceus. Will-O-Wisp and the Ghost Typing can wall Ekiller very well, and can set up Stealth Rocks and use its perfect coverage.
Ghosteus set:

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Arceus-Ghost @ Spooky Plate
Ability: Multitype
EVS: 252 HP, 252 Defence, 4 Special Attack
Will-o-Wisp
Stealth Rock
Judgement
Focus Blast

Thanks for the advice! While sometimes My arceus lets me down I still feel that his role on the team is not a defender but a surprise attacker. I can try it out and see if I like it!