First of all, these sets are for Nat Dex AG, not Gen 7 AG, I can tell easily.
This can be easily told from the fact that Dusk Mane is physically defensive to stop Zacian-Crowned, which doesn't exist at first place in Gen 7. It needs to be specially defensive to stop Xerneas, else we gonna see the team swept by Geomancy Xerneas.
Necrozma-DM
A fully specially defensive EV spread makes Necrozma-DM a strong check to Xerneas and the majority of support Arceus formes. The EV spread also allows Necrozma-DM to avoid 2HKO from support Arceus-Ground's Judgment, letting it stall out Arceus-Ground with Toxic.
Leftovers provide Necrozma-DM with passive recovery, increasing its resilience to residual damage and lessening its reliance on Morning Sun. Solganium Z can be used to give Necrozma-DM a significantly greater offensive presence and prevent Gothitelle from trapping and neutralizing it.
A physically defensive EV spread of 252 HP / 252 Def / 4 SpD with an Impish nature can be used to better handle Mega Salamence and Rayquaza and even avoid 2HKO from Life Orb Marshadow with Leftovers recovery.
Marshadow is beaten by Yveltal easily, while M-Salamence and M-Rayquaza are checked both by Defensive Fairyceus.
So, the set should be:
Necrozma-Dusk-Mane @ Solganium Z/Leftovers
Ability: Prism Armor
Careful Nature
EVs: 252 HP / 4 Def / 252 Sp.Def
- Photon Geyser -> Toxic/Swords Dance
- Sunsteel Strike
- Stealth Rock
- Morning Sun
Yveltal
Secondly, coming to Yveltal. Is this set for even for Gen 7 AG, or for a Dynamax Yveltal set which doesn't even exist in Gen 7?
Zacian-Crowned doesn't exist in Gen 7, you don't need Heat Wave. Tyanitar isn't much common and Focus Blast therefore is unneeded. Get Yveltal to have a Choice Scarf, here's why:
Foul Play is used on this set because Choice Scarf Yveltal's lack of firepower otherwise makes it hard to KO even offensive threats, and Choice Scarf allows Yveltal to usually use Foul Play before the opponent can attack, turning their own Attack boosts and investment against them. For example, Foul Play can OHKO +2 Swords Dance Arceus-Ground and Choice Band Mega Rayquaza.
Maximum Speed investment coupled with a Choice Scarf allows Yveltal to outpace many threats, notably including Deoxys-A, Mewtwo, Ultra Necrozma, Mega Gengar, Marshadow, and all Arceus formes.
This is very important to beat Ultra Necrozma, since it sweeps this team after a +2 Swords Dance, which is why Choice Scarf is chosen. Life Orb sets are best viable in Nat Dex AG, where non-LO sets have lost viability, due to Ultra Necrozma getting Dragon Dance in Gen 8, which allows to outpace Scarf Yveltal.
Arceus-Fairy
Specially Defensive sweeper Arceus-Fairy? Geomancy Xerneas is better in all ways possible. You can look at Smogon explanations here: https://www.smogon.com/dex/sm/pokemon/arceus-fairy/ag/. All sets recommend physically Defensive Fairyceus, as a support, while 252 Hp/252 Spe for Calm Mind. Use physically defensive Arceus-Fairy to stop Mega-Rayquaza, Marshadow, etc. or as a Defog/ Refresh support.
Arceus-Fairy is a staple within the Anything Goes metagame thanks to its great offensive and defensive typing, expansive movepool, and impressive natural bulk. Due to this, it can reliably take on many potent threats within the metagame, such as Mega Rayquaza, Marshadow, Mega Sableye, Yveltal, and Zygarde-C. The ability to check these Pokemon makes Arceus-Fairy incredibly useful on balance teams that are often threatened by them otherwise. Arceus-Fairy's extensive movepool also allows it to be relatively unpredictable, with access to a plethora of coverage and status moves. This allows Arceus-Fairy to take on or impair most threats without much difficulty.
Most of the mentioned attackers are physical ones, that's why Smogon recommends Physically defensive sets.
16 Speed EVs enable Arceus-Fairy to outspeed maximum Speed neutral-natured base 90s, such as Primal Kyogre and Primal Groudon. The rest of the EVs are invested into its physical bulk in order to maximize its chances of surviving a +1 Mega Rayquaza's Dragon Ascent after Stealth Rock damage. Alternatively, Arceus-Fairy can run the same set with 248 HP / 8 SpA / 252 Spe and a Timid nature to outspeed Mega Rayquaza and Speed tie with other maximum Speed Arceus formes. Pixie Plate gives Arceus-Fairy's already potent Judgment a slight boost.
The set:
Arceus-Fairy @ Pixie Plate
Ability: Multitype
EVs: 248 HP / 244 Def / 16 Spe
Bold Nature
- Judgment
- Recover
- Stealth Rock/ Defog
- Toxic/ Will-O-Wisp
Defog support is important primarily against Sticky Webs team, while Toxic beats other support Arceus formes while Will-O-Wisp cripples Dusk Mane.
Alternatively, Earth Power can be run to beat Primal Groudon but Toxic stalling it is much better.
Primal Kyogre
Seems solid.
Aegislash
Why are you using this? To check Xerneas and Mega-Lucario?
Xerneas is easily checked by Dusk Mane, while Mega-Lucario is nowhere as common as M-Ray, which Aegislash can't even touch it, to get OHKOed by V-Create. As such, there's no reason to use this.
I recommend getting rid of Aegislash and having another physical attacker, like Extreme Killer. It is definitely better than Aegislash on offensive Swords Dance sets, so it is better than Aegislash, which doesn't even have a Smogon analysis.
Aegislash is both outclassed by Dusk Mane for checking Xerneas while Marshadow is the better ghost-type than it for threatening M-Gengar, etc.
Arceus @ Chople Berry / Life Orb
Ability: Multitype
EVs: 252 HP / 252 Atk / 4 SpD OR 252 Atk/ 4 SpD/ 252 Spe
Adamant Nature / Jolly Nature
- Swords Dance
- Extreme Speed
- Recover / Earthquake
- Shadow Claw
It's your decision to whether choose Bulky Killer or fast Killer. SD is set-up, while Extreme Speed is priority and the best normal type priority and move on Arceus. Chople Berry along with 252 HP helps against M-Lucario, Marshadow, etc. while Recover on bulky sets help it against setting up Swords Dance better against Arceus support formes. On the other hand Earthquake with Life Orb at +2 has good chance to OHKO Dusk Mane including Primal Groudon. Shadow Claw is chosen over Shadow Force since the latter allows the Pokemon to escape, while both deal with Marshadow. Earthquake can not be chosen since +2 Shadow Claw without Life Orb 2OHKOes most Dusk Mane variants.
Mega Rayquaza
Choice Band is an amazing wall breaker, and if you use Extreme Killer then you don't need Dragon Dance Life Orb. However, why both V-Create and Earthquake? Swap out one for Extreme Speed if you need to beat other M-Rays and revenge killing stuff apart from Yveltal. And Outrage is very bad. Being locked to one move means Xerneas can freely set-up. Hence, choose a mixed set with Draco Meteor or even Waterfall/Surf (for the lols, actually OHKOes Primal Groudon most of the times).
Updated team: https://pokepast.es/805f4ee2eb101fda
Hope I helped.
