I should start off by saying that in order to properly embrace competitive battling, EVs are going to be supremely useful not just to you, but to people rating teams as well.
Greninja set looks very nice, but as already suggested by wilsonna1, a different nature would be a good idea. That said, Timid weakens U-turn and Rock Slide so Hasty might be better off.
No real issues with Togekiss or Ferrothorn
You may want to consider giving Alakazam Psyshock instead of Psychic in order to help it deal with common specially defensive problems such as Chansey and Blissey
Volcarona looks good as well
Garchomp definitely needs a different nature, as Quiet is taking away from its Speed whilst boosting Special Attack, and Garchomp has no special attacks to work with. Jolly, the opposite nature, would be an ideal solution