Chromatic Arceus

Hey all. I had a thought this morning. Arceus is the God of Pokemon, and is technically all types. This is emulated in the main series with Arceus being able to switch types. In Pokemon GO, things are different. It is possible for Niantic to release Arceus as Chromatically typed, all types combined.
With this thought, I came home from work and worked out the mathematics. I wanted to know how well each type performs against Arceus on offense and defense. Here's what I ended up with. (TL;DR below)

Starting with the worst attackers, we have BUG, GRASS, NORMAL, and POISON. These types are resisted 4x by a Chromatic type.
Not quite in last place, but very close, is ELECTRIC. Electric is resisted 3x by Chromatic types.
Next, we have PSYCHIC, FIGHTING, and DRAGON. These types are resisted twice by Chromatics.
These next types almost break even, being resisted once by a Chromatic Arceus. These are DARK, GHOST, and STEEL.

Now we get to the fun stuff. These attackers do not deal super-effective damage, but they are not resisted either, dealing 1x damage. These are FAIRY, FIRE, FLYING, ICE, and WATER.
Finally, the types that deal supereffective damage (2x), we have GROUND and ROCK.

Before you dump stardust into your Golems and Rhyperiors, let's talk about Arceus's potential movesets. He is the Pokemon God, meaning he can learn any move in the game. For this proof, we'll assume that every move is included in his movepool, and that he uses only 1 charged move. The exception to this are the abilities Yawn, Transform, and Splash.
The chance of Arceus having X typed move is as follows:
Fast Moves
Fairy: 0%
Dragon, Ground, and Rock: 4.1%
Fire, Flying, Grass, Ice, Poison, and Water: 5.4%
Bug, Dark, Electric, Fighting, Ghost, Psychic, and Steel: 6.8%
Normal: 8.1%

Charged Moves
Dark: 3.1%
Bug, Dragon, Fairy, and Ghost: 3.9%
Electric, Flying, Poison: 4.7%
Fighting, Ice, Rock, Steel: 5.5%
Ground and Psychic: 6.2%
Grass: 7%
Fire: 7.8%
Water: 8.6%
Normal: 9.4%

That information is cool, but it doesn't tell us anything yet. We'll use the numbers above to calculate how well Arceus performs against the 7 types plus Steel (because Steel is fucking amazing).
The chance that Arceus has a FAST move that counters / is resisted by these types is:
Fairy: 12.2% / 24.5%
Fire: 13.6% / 29.8%
Flying: 16.3% / 23.1%
Ground: 16.2% / 16.3%
Ice: 23.1% / 5.4%
Rock: 28.5% / 24.3%
Water: 12.2% / 23%
Steel: 14.9% / 58.3%

The chance that Arceus has a CHARGED move that counters / is resisted by these types is:
Fairy: 10.2% / 16.4%
Fire: 20.3% / 33.6%
Flying: 15.7% / 22.6%
Ground: 21.1% / 14.9%
Ice: 24.3% / 5.5%
Rock: 32.8% / 26.6%
Water: 11.7% / 27.4%
Steel: 19.5% / 60.2%

We'll now assign a score to each type, using this formula
(((Fast Resist - Fast Counter)/2) + (Charge Resist - Charge Counter) + 28.65) / 50.05
The scores for each type are as follows:
Fairy: 82
Fire: 100
Flying: 78
Ground: 45
Ice: 2
Rock: 41
Water: 99
Steel: 182*
*This type should only be used as a dual type for its defensive value. No Steel type moves should be used, as Steel is resisted by Chromatic Arceus.

With these scores, let's look at potential attackers to fight Arceus!
Tyranitar, Golem, Groudon, and Rhyperior are reasonable fighters to deal super-effective damage, but the chance of facing an Arceus with a counter moveset is high. Aggron has a lower chance of being countered, but his DPS would be low (no Rock fast move, low attack)

In the event you'd prefer to lose less Pokemon per raid, these fighters will deal neutral damage and survive longer.
Moltres, Entei, Charizard, and Flareon are likely to do well. Heatran can fill out your team as a tank counter.
Kyogre, Gyarados, and Feraligatr are within 5% of the Fire types. Empoleon serves as another tank counter.
Should you desire to use Fairies, Togekiss is the only realistic choice. Gardevoir and Clefable both have terrible fast moves against Chromatic types.
Rayquaza or Dragonite with a double flying moveset should perform well, so long as Arceus is not using any Ice moves. Staraptor and Honchkrow can also be used.

TL;DR
One way to add the God of Pokemon to GO would be to make its type Chromatic. A Chromatic type is all 18 types combined into one. A Chromatic Arceus is weak only to Ground and Rock, and takes neutral damage from Fairy, Fire, Flying, Ground, and Ice. If you can pair any of those types with Steel, you'll solidify your place in the raid.
Ground and Rock Pokemon have the highest DPS, but have a high chance to find an Arceus with a counter moveset. The other 5 types have wonderful options that will have lower DPS, but a much higher survival rate.