My friend and I are constructing a battle tower team (3rd gen) to do a joint battle against it.
I have constructed my half to compliment his.
His team I can't be very specific as he didn't tell me much, all I know is;

Milotic, Salamence and Metagross.
he told me the move types;
-dragon
-flying
-water
-ice
-psychic
-steel
-fighting
and
-normal

So I constructed this team from his weaknesses, my weaknesses, the types he's not effective against, STAB and battle roles.
This is what I came up with;

@Quick Claw / Leftovers
Rock Head - Adamant / Brave
252 Atk / 252 HP / 6 Def
Earthquake
Rock Slide
Double-Edge / Toxic
Rest / Protect

@Scope Lens / Shell Bell
Flash Fire - Modest
252 SpAtk / 252 Spd / 6 HP
Flamethrower
Crunch
Sunny Day
Sludge Bomb / Double-Team

@Bright Powder / Leftovers
Effect Spore - Mild
252 SpAtk / 252 Atk / 6 Speed
Solarbeam
Sky Uppercut
Leech Seed
Helping Hand

what I would like to know is if you can do better, not necessarily these pokemon but any pokemon that fit the role, what I'd like to see is a team that compliments itself by having a super effective hit on every type, including it's weaknesses with no major flaws. The only limit is it's 3rd gen.

I dnt lkike the idea of Golem u can do much better like alakazam, Houndoom and Aerodactyl is you can good combos and keep houndoom moveset

{Alakazam}:Syncornise, @Leftovers: Modest
~ Calm Mind
~ Psychic
~ Fire Punch
~Thunder punch or ice punch or recover or Hidden Power Water

{Aerodactyl}: Rockhead @Choiced band Jolly
~ Hidden Power Flying / Hidden Power Ghost
~ Rock Slide
~ Earthquake
~ Double-Edge

No you've missed the point, the idea was to get super effective against every type, get a STAB bonus, not clash with the same types and have no major weakness, not to choose which pokemon you favor.

Instead of Breloom you should get an electic type like Amphiros or raichu or manectrike.