With Tyranitar trapping Lati@s as it is, I decided to go with a Landorus-I + Manaphy offensive core since they're so dangerous and unnecessarily powerful in tandem with Lati@s gone. RP Landorus-I beats offense and weakened balance pretty handily, and TG RD Manaphy is probably the biggest threat to stall and balance too. Manaphy has enough speed to outspeed positive nature base 80s and then the rest in bulk to last longer against fat teams that doesn't have much offensive pressure, as well as take on SD Gliscor more efficiently. Energy Ball is nice because it weakens Rotom-W (kills if you're at +3) so Landorus-I can take it out with Sludge Wave later, and beats CM M-Slowbro and Crocune, plus it breaks M-Gyarados' Substitutes.
For the defensive backbone there's Jirachi to check a majority of the Fairies in the tier, get up Rocks, weaken Ferrothorn for Lando and Manaphy with Fire Punch (as well as dent M-Scizor), and Healing Wish since two Manaphy vs Stall is gg, same with two Landorus-I vs balance. AV Tangrowth is just a lord since it checks Azumarill, Bisharp, Keldeo, Thundurus, M-Diancie, M-Lopunny, Landorus-T (and Landorus-I if it doesn't have Sludge Wave), Excadrill, Rotom-W, Breloom, Garchomp, Slowbro etc. Leaf Storm can be used over Giga Drain for some offensive presence rather than longevity.
Lastly there's Scarf Latios for speed control, largely there to check Zard X and all Swift Swim users barring Kingdra that run 232 or more EVs in Speed. Being able to trick a Scarf to Ferrothorn, Clefable, Chansey, etc is also very helpful. Scarf Defog is pretty ridiculous but Spikes are annoying since two thirds of the team is grounded, plus only one member doesn't take the normal 12% damage from SR, so it's useful.
No mega, but they're not really necessary on every team.