Pokémon Omega Ruby & Alpha Sapphire

Salamence, Mega
Nature ~ Jolly
Ev spread ~ 252 attack and speed, 4 hp
Move spread ~ Dragon Dance, Double Edge, Fire Fang, Earthquake

This is the standard dragon dance set, only with some changes to account for its ability.  I decided running a dragon move wasn't worth the effort as it was either the relatively weak Dragon Claw or Outrage, the former was too weak to warrant a slot that could be used for coverage and the latter leaves you too open with fairy types around, last thing you want is for a mega Mawile to come in and get a free Swords Dance off.  

I was tempted to put Substitute on the set over fire fang, and in hindsight I kind of wish I had as there aren't any real notable walls in the hoenn dex that can stop salamence that aren't already dealt with by double edge, but what's done is done and the team's registered now.

Metagross
Item ~ Assault Vest
Nature ~ Adamant
Ev Spread ~ 252 HP and attack, 4 special defense
Move spread ~ Meteor Mash, Zen Headbutt, Ice Punch, Earthquake

When I was building the team my first thought was what I would do about Mega Salamence checks, specifically scarfed gardevoir.  Immediately my mind turned to Metagross, gardevoir even if it chooses to run shadow ball isn't doing much against a bulky one, and the assault vest means it can tank most special moves in general while also completely walling the one sure fire check Salamence has.

Breloom
Item ~ Focus Sash
Nature ~ Adamant
Ability ~ Technician
Ev spread ~ 252 attack and speed, 4 hp
Move spread ~ Mach Punch, Spore, Rock Tomb, Bullet Seed

This one's a standard offensive techbreloom, focus sash will allow it to spore even something that can normally kill it )which is a lot of things) and then do any number of things from slowing it down with Rock Tomb (while inflicting nice damage thanks to the technician boost), using mach punch, or trying my luck with bullet seed.  It also takes care of any stalling water types, which are fairly common in hoenn.  Mach Punch will also cover the speedier ones like Sharpedo and crawdnaught, both of which are threats in general.

Gardevoir
Item ~ Choice Scarf
Nature ~ Timid
Ev Spread ~ 252 special attack and speed, 4 hp
Move spread ~ Moon blast, thunderbolt, psychic, blank spot (actual move is stored power. . .)

My answer to Mega Salamence if it kills any of the team without dragon dancing once.  Most of the team is equiped to deal with it should it try to set up, and this is here to deal with it when it decides to go straight for the kill.  Honestly that's pretty much the entire role this pokemon is here to cater to, although scarfed moon blast comes in handy from time to time, especially in the doubles arena which I raised it for.  The last move should be hidden power, but I just didn't have time to rebreed another one since I spent the last four days breeding a contrary snivy for hidden power ice.

Milotic
Item ~ Leftovers
Nature ~ Modest
Ev Spread ~ 252 HP and special attack, 4 special defence
Move spread ~ Scald, ice beam, recover, dragon tail

The replacement of walrein, the general idea for this thing is to basically scald things until they burn while using recover to heal up when needed, then dragon tail and repeat until either the team is completely burned or it gets taken out.  It's basically designed to be a real nuisance and shuffle things a lot while dealing proper damage and ailments when it gets the chance.  I could have gone for even more bulk, but I decided that because it's toxic bait I'd go for damage in the short term as singles wi-fi matches are very short and what would normally be a small advantage in a longer full team match is a far bigger advantage in the shorter form of the game.  It's kind of like 20/twenty cricket compared to Test cricket, each form of the game has different priorities.

Dusclops
Item ~ Eviolite
Nature ~ Relaxed
Ev spread ~ 252 hp and defence, 4 special defence
Move spread ~ Pain Split, Will-o-wisp, shadow sneak, night shade

The last member of the team, this is my answer for metagross of all varieties as well as any physical threat that isn't dark type.  It cannot be stressed enough how well this can tank physical attacks, and once it gets the burn on the enemy the physical attacker might as well be dead already with the progress they'll make.  Eviolite takes its already high base 130 defences and then boosts them even further, in fact the only thing stopping this from being borderline broken is the abundance of knock off and the fact it has no true reliable recovery.  Generally speaking bisharp absolutely crushes this, but hoenn only its only real threats are mega sharpedo, absol, and crawdnaugt.  

It also tanks special attacks very well, while its aim is to deal with physical threats it can still deal some nice damage to a special attacker before it goes down.  

Item - Life orb
Ability - Sheer Force
Nature - Adamant or Jolly
Ev spread - 252 attack, 160 speed, 96 hp
Moves
Dragon Dance
Aqua Tail
Crunch
Rock Slide / Earthquake / Ice Punch