UPDATE TIME!
Word: Physical.
Trained everyone until level 44 (except for Zeus, who was level 46 but that doesn't matter anyway, it wasn't used). After that, challenged the E4.
Will wasn't too hard. Winnie could take care of the Xatus with Slash, Jaws Bited Slowbro and Ice Punched Exeguttor. It also helped me with Jynx, who is so fast it really REALLY annoyed me. Norris then Strenght'd it for the kill.
Koga was ridiculous. Sandwich just EQ'd and Rollout'd stuff and it was done.
Bruno wasn't hard either. Winnie's Slashes, Sandwiches' EQs and Norris' Hi Jump Kicks quickly disposed of them.
Norris was also MVP against Karen. Pretty much an Hi Jump Kick sweep, except for Gengar, who went down in two Hidden Power Ghosts by Winnie, and Murkrow, who got Tpunched by the same Winnie.
Lance was way too easy. Winnie TPunched Gyara, then Jaws Ice punched the three Dragonites. After that, all I had were a weakened Winnie, Norris, and Sandwich. I knew Aerodactyl would be faster than me, so I lured an Hyper Beam of his with Winnie, thus bringing Sandwich safely (recharge turns = lol) and Rollouting him to death. Once Charizard came, he hardly had any time to blink. Quad weakness owned him.
While getting the badges, Zeus finally evolved, and I got my 6th member! In the Celadon game corner, I saw Larvitar. 'What the hell?', I thought. I had no idea I could get one of those there. Well, I did. I got a Larvitar, named it Khaos, and swapped the Exp. Share from Zeus to him. Zeus went to the box (no need to train him more, he was 7 levels ahead of all the others), and I kept sweeping gyms. Gary was the toughest, but even still, nothing worth mentioning.
Beat the E4 one more time, so that Khaos would evolve into his final form.
Red's battle was the only thing remaining. Here's my team for the battle.

Sandwich, the level 50 Sandslash @ Amulet Coin
~ Slash
~ Earthquake
~ Rollout
~ Hidden Power [Flying]
Lost a bit of its magic, but still useful in general. Physically quite bulky, and capable of consistent damage. Not my biggest asset, but still, pretty decent. Improved drastically with EQ. HP Flying didn't really come to play.

Jaws, the level 50 Feraligtr @ Mystic Water
~ Surf
~ Ice Punch
~ Slash
~ Iron Tail
Mediocre at best. He really played a very minor role on this playthrough. His Ice Punch was very appreciated against Lance, and part of his special bulkyness was useful as well against Red, as you will see later. However, on the wider perspective, he wasn't that great.

Winnie, the level 50 Ursaring @ Bitter Berry
~ Return
~ Thunderpunch
~ Dynamicpunch
~ Hidden Power [Ghost]
Quite useful. His Return was VERY powerful, and Hidden Power Ghost was a blessing against those pesky psychics. Specially the Alakazams. Thunderpunch provided some very needed coverage against water types, and also helped dealing with some fliers. All in all, a very reliable member of my team. Though he couldn't take hits all day, he was a very good revenge killer.

Norris, the level 50 Hitmonlee @ Quick Claw
~ Strength
~ Mega Kick
~ Hi Jump Kick
~ Endure
Never got to use Endure, because I never got Reversal. That moveset, while not providing great coverage, made Hitmonlee a beast. It gave him enough power to pretty much 2HKO everything (sans Red's pokes), if not OHKO. Definetly my main source of fast damage, and a nice special wall sometimes too. While is HP isn't anything spectacular, his Special defense was very appreciated at times.

Zeus, the level 56 Dragonite @ MysteryBerry
~ Wing Attack
~ Extremespeed
~ Curse
~ Rest
Yes, the Cursespeed set. Curse up for massive attack boosts, then Extremespeed. Went for Wing Attack instead of Surf because of STAB mainly. And I already had a STAB'd Surf on my team.
Barely used him, to be honest: only on Gary's and Red's fight. Before that, he was mainly a Dragonair, so...
He also added my team some VERY significant resistances to Grass and Water moves.

Khaos, the level 55 Tyranitar @ Nevermeltice
~ Ice Beam
~ Thunderbolt
~ Crunch
~ Rock Slide
Yes, a special-based Tyranitar. I needed the BoltBeam, and thought originally of giving it to Zeus. However, he already had the Cursespeed set. So I decided to give it to Tyranitar.
Belive it or not, adding Tyranitar and Dragonite to my team made it more of a challenge. They were only truly used on Red's fight, so until then, all they did was suck on my team member's Experience. Nevertheless, let's proceed. It's time for Red.
Red's fight started of well. Sandwich vs Pikachu. Pikachu would Charm, I EQ'd, he Full Restored, I EQ'd, he Full Resotred, I EQ'd again, he Quick Attacked, and I EQ'd for the kill. One Pikachu and 2 Full Restores down.
Next, it was Venusaur. My ONLY way of beating this thing was with Dragonite. Seriously, I was like 30 levels lower than him. So I Wing Attacked until he was dead. So far, so good.
The main pain in the butt would come now. Blastoise. In the rain, that thing could Surf OHKO EVERYTHING on my team, except Gater and Dragonite (which he could OHKO with Blizzard). So I brought in Sandwich, thinking he'd be faster, but he wasn't. I brought in Winnie for Tpunch, then he fainted. Brought in Norris for a little bit more damage, but he fainted right away too. THEN brought Jaws, as he could resist the Surfs quite well. THANK YOU JAWS, FOR ACTUALLY BEING USEFUL ASIDE FROM YOUR ICE PUNCHING! By the time Jaws was defeated, Blastoise had around 20% HP. Right in the range for...
Zeus to come in and Extremespeed him. Dead Blastoise. Yay!
Espeon came, and got so walled by Khaos it wasn't even funny. From them on, I just Crunched Espeon, and Rock Slided Snorlax and Charizard for my victory on this final match.
And so, Red was defeated by a team which you could call Physical, and around 30 levels lower too! :)