I have a character who has four arms. Are there any rules for characters with multiple arms wielding two two-handed weapons or using all of their arms to hold one huge (if the character is medium) weapon?

If it is possible to dual-wield two-handed weapons, would both two-weapon fighting feats *and* feats that affect two-handed weapons apply to attacks? For example if the character had [improved two weapon fighting](http://www.d20pfsrd.com/feats/combat-feats/improved-two-weapon-fighting-combat---final) (ITWF), [Two-Weapon Defense](http://www.d20pfsrd.com/feats/combat-feats/two-weapon-defense-combat---final) (TWD), and [Power Attack](http://www.d20pfsrd.com/feats/combat-feats/power-attack-combat---final) (PA), would the character get 2 off hand attacks from ITWF, deal 1.5× STR damage from PA, and get +1 AC from TWD?

I would prefer official rules but was unable to find any myself, so I will accept houserules/homebrew as well.