
Kaelizar |

As noted on Paizo
Can I take a 5-foot step in the middle of my attempt to use the Cleave feat, to bring another foe within reach?
No. Cleave is a special action and the conditions for that action are checked at the moment you begin your action. At that moment, all of the available targets are checked to make sure they adjacent to each other and within reach. You cannot take a 5-foot step in the middle of the action and check conditions again. If you do not have two targets within reach, adjacent to each other at the start of the attack, you could not even attempt to make an attack using Cleave.
Taking this as written, because Cleave is a special action, it seems no other combat action could be considered unless specifically stated. So no Charging, no TWF, nothing that requires an action to be expended.

Joex The Pale |

I'm thinking that the attack that triggers the cleave is one action that then triggers a new action, which then gets resolved before returning to the previous action, already in progress. Would that not be accurate? If the fighter in question made a full attack action against one of three opponents in reach, hits, cleaves into a second and drops them both, he could then return to his full attack action, which the cleave interrupted, and target the third, no?

Grick |

If the fighter in question made a full attack action against one of three opponents in reach, hits, cleaves into a second and drops them both, he could then return to his full attack action, which the cleave interrupted, and target the third, no?
No, because as previously mentioned, Cleave is a standard action, and you (usually) can't take both a standard action and a full round action in the same turn.

Marthian |

On it's own, no. But if you have Cleaving Finish, assuming you down the target, you can cleave into another target.
I don't really think either Two Weapon Fighting or Cleave is a feat trap, but it is a lot of feats.
EDIT: Even if you only have a Standard Action, Cleave is still good if you can do it, as is Vital Strike (ignoring the oddity that is Charge doesn't let you Vital Strike as well.)