Volt Absorb anyday. While Lanturn resists Water, it is neutral to Electric, so it is better overall. Also, Smogon says Volt Absorb is better which I totally agree with. Now, I am assuming this is for the Battle Tree by your wording as well as Online Battles. So, for a Good Teammate, I would probably go with Mega Manetric. Mega Manetric Has Base 135/135 SpA. And Speed to give a high chance to get off a move to heal Lanturn. Also, with access to Discharge, you can damage opponents as well as Heal Lanturn. Also, Manetric Has the great Ability of Intimidate, as well as access to Snarl, I would say Mega Manetric makes a good Teammate.
Lightning Rod -> Intimidate.
252 Spd/252 SpA/ 4 Defense.
-Protect/Overheat/Hidden Power Ice. Your Choice. I would opt for Protect or Hidden Power Ice to cover Weaknesses.
Hope this helps!