The standout threats for me on against this team are:
Ho-oh in the sun is extremely dangerous
and while Stealth Rock will do a number on it, the thanksgiving turkey will remain a constant thorn in your side because the only person on your team that can hope for a KO currently is Arceus.
+2 Extremespeed w/o Life Orb 252 Atk vs 248 HP/ 0 DEF Adamant Ho-oh : 71.57 - 84.1% guaranteed 2HKO
Unfortunately in the case of a sub Ho-oh you will not have any opportunity to SD
so it can easily 2HKO you in return
Sacred Fire (SUN) w/o Life Orb 168 Atk vs 4 HP/ 0 Def Adamant Arceus : 56.69 - 66.93% guaranteed 2HKO
Although Groudon does have Stone Edge you have invested minimal Attack or Speed EV's so Ho-oh can simply stall out Stone Edge and burn with Sacred Fire. Dragon Tail will fail to phaze Ho-oh as even unburned it will fail to break its Substitutes.
Stone Edge (BURNED) w/o Life Orb 4 Atk Groudon vs 248 HP/ 0 Def Adamant Ho-oh (ROOST) : 26.99 - 32.29% 4-5 hits to KO
While Jumpluff would be a thorn in Ho-oh's side with encore against Substitute it does not want to mispredict and eat a Brave Bird or Sacred Fire. Even Palkia won't be able to revenge
Surf (SUN) w/o Life Orb 252 SAtk Timid Palkia vs 248 HP/ 84 SDef Ho-oh : 27.47 - 32.53% 4-5 hits to KO
Brave Bird w/o Life Orb 168 Atk Adamant Ho-oh vs 4 HP/ 0 Def Timid Palkia : 42.37 - 49.84% guaranteed 2HKO after SR
The second biggest threat i can see is SAND and more specifically Excadrill
Sand will also have a huge advantage against this team because it can take away Jumpluff's speed, Blazikens strength and give your opponent a massive advantage. Excadrill in the sand will singlehandedly 6-0 you
. Even Groudon will be KO'd
before you can do anything to it.
+2 Earthquake w/ Life Orb 252 Atk Adamant Excadrill vs 252 HP/ 252 Def Impish Groudon : 67.57 - 79.48% guaranteed 2HKO
While Life Orb Excadrill does hit like a truck it isn't as dangerous as Air Balloons Excadrill
because Groudon can simply KO back with Earthquake however Air Balloons Excadrill will also hit hard and KO you before you can touch it
. It doesn't even need Jolly because it will oustpeed everything on your team including +2 Blaziken in the sun
+2 Earthquake w/o Life Orb
252 Atk Adamant Excadrill vs 252 HP/ 252 Def Impish Groudon : 51.98 - 61.14% guaranteed 2HKO
even the more common (with Air Balloon) Jolly Excadrill will do:
+2 Earthquake w/o Life Orb 252 Atk Jolly Excadrill vs 252 HP/ 252 Def Impish Groudon : 47.52 - 55.94% ~80% chance to 2HKO after Stealth Rock
After Groudon is KO'd your entire team is OHKO'd by a +2 Excadrill with the exception of Ferrothorn who is set up fodder allowing to to belt even more SD's. Excadrill can't even be revenge killed by Arceus
thanks to his Steel typing.
Extremespeed w/o Life Orb 252 Atk Adamant Arceus vs 4 HP/ 0 Def Excadrill : 28.18 - 33.43% 3-4 Hits to KO