Team member #5 maybe? I love this guy :)
Bouffalant (M) @ Choice Band
Ability: Sap Sipper/Reckless
EVs: 252 HP/252 Atk/4 Def
Nature: Adamant/Impish
-Head Charge
-Megahorn
-Stone Edge
-Wild Charge/Earthquake/Revenge
This would be the Choice Bander of the team, hitting nearly anything very hard. Head Charge is the best STAB, though the recoil hurts, especially without Rest or other recovery. Megahorn makes Bouffalant a great counter to Lilligant and Tangrowth if it runs Sap Sipper, because it can come in on Sleep Powder/Leech Seed/STAB move, gain an attack boost, and proceed to quickly eliminate both of them with CB-boosted Megahorn. Neither can do much back to Bouffalant because of its bulk, and they virtually never run HP Fighting. Stone Edge helps with Charizard and Typhlosion, plus Flying-types (this set destroys all Cryogonal with any move besides Earthquake). Wild Charge is preferred to destroy bulky waters (excluding Quagsire), but Earthquake can be used for Steels (mainly Aggron), but so can Revenge, which will usually be a BP 120 move due to -1 priority.
Could this be a potential fifth team member? The amazing combination of power and bulk plus being a sleep absorber (outside of Hypnosis) makes it worthy of a spot on the team (not being weak to Stealth Rock is a plus).
EDIT: I looked up a Calc, and +1 CB Bouffalant has an easy 2HKO on 252/252+ Tangrowth with Megahorn with an Impish nature, and a chance to OHKO with Adamant.