The way i think Halo 4's forge list will turn out (Other weapons)

Brute Weapons(Only if they are in the game)
Type-25 Carbine(Spiker)
Type-25 directed Energy Rifle(Red Plasma Rifle)
Type-52 Pistal(Mauler)
Type-25 Grenade Launcher (Brute Shot)
Type-2 Energy hammer (GRAV HAM)
Type-2 antipersonel frag (Spike grenades)
Type-3 Incendiary Grenades

Other weapons
Scarab Gun (For the LOLz!)
Type-51 Plasma Repeater
type-1 energy sword
type-51 carbine
Type-25 Plasma Rifle
Type-25 Plasma pistol
Type-50 Beam Rifle
Needler
Sentinel Beam
Fuel Rod Gun
Others

Brute weapons need to be in the game even if there are no brutes.