Life Orb and U-Turn is not the best combo for a physical Greninja from my experience, especially if hazards are on the field.This is the Greninja I use.
Everyone tells me Water Shuriken is a niche move, but it has been great for me, especially on raindance teams. It's priority is quite useful vs Talonflame.
Grass Knot is also great. It has a cool trick vs Smeargle where you can grass knot them, breaking their sash and also making Greninja immune to spore.
The STAB Life orb U-turn hits like a tank.
MIXED ATTACK GRENINJA
Adamant/Jolly
252 Speed, 252 Attack 4 HP
Ice Beam
Water Shuriken
U-Turn
Grass Knot
The only weak move is Ice Beam, does anyone have a better suggestion? This greninja gets walled by steels.