Can a figure with multiple ranged attacks make multiple attacks using "energy explosion"? The rule states "Give this character A ranged combat action. . . ."

Does enhancement affect "energy explosion" to increase the damage inflicted to 2?

Yes and yes.

Energy Explosion is a single attack, that can have multiple targets. Dont' confuse multiple targets with multiple attacks.

Both SHIELD and Enhancement will bump up EE attacks, and Pulse Wave attacks for that matter.