Just gonna say that Team 2's Mamoswine probably wants Thick Fat over Oblivious... the tea would really like an Ice resist.
Now, let's take a good look at team 2. 3 Water weaknesses and 2 Ice weaknesses. They're also using Sand with an Excadrill, which means that we really don't want them to keep the weather up. I mean c'mon, the team basically just screams: "Kyogre weak!"
A fast Kyogre would outspeed all of Hippowdon, Mamoswine and Excadrill. Team 1 could do with a nice heavy hitter right off the bat, so I'm gonna suggest Choice Specs Kyogre.
EDIT: Hold on. It OHKOs Lugia as well with Stealth Rock support. Know what this means? At the moment Choice Specs Kyogre can OUTSPEED and OHKO ALL of team 2 (SR needed for Lugia) Here are some calcs against Lugia (none needed for the other three):
Water Spout: 69.95 - 82.45%
Surf: 44.71 - 52.64%
Thunder: 74.51 - 87.98%
Ice Beam: 59.61 - 70.19%
Seeing as Kyogre outspeeds Lugia, nothing on team 2 is safe. At all. Kyogre only needs SR for Surf to 2HKO, it doesn't even need SR for all three other attacks to 2HKO. It truly is the bane of team 2 at the moment.
Kyogre @ Choice Specs
Modest / Drizzle
EVs: 4 HP / 252 SpA / 252 Spe
- Water Spout
- Surf
- Thunder
- Ice Beam
Max Speed to outrun Mamoswine and Excadrill, Water Spout can basically always net Team 1 a kill from now on. Surf is preferred over Hydro Pump as Kyogre doesn't need the extra power to destroy Team 2. Thunder and Ice Beam are obvious options on Kyogre, but they're also there so that it can smack Lugia around. Team 1 does't rely on Sun being up at all at the moment, so it's not like it clashes with Groudon at all.
Obviously the main reason to use it is because having Groudon, Kyogre and Rayquaza on a team together is super-duper awesome.