will the alliance fleets affect the members power. eg: will it bump them up into someone elses attack range if they have the alliance fleets defending them?
No, the alliance fleet protecting the alliance member will not boost the member power, because that wouldn't help the member much, would be just like having some extra fleets.
The alliance fleets will protect the member at a lower power, making his defense more powerful. For example at 10 mil mothership power, the member can receive a 5 mil alliance fleet power protecting him. This means that when someone wants to attack the member, they would have to face some extra fleets, that is the alliance fleets, at a lower power that is the member power. So on defense, the member benefits from the alliance protection.
He can then just choose to have some main mission fleets, and if the alliance protects him, the alliance fleets will be above his mission fleets when on defense, effectively protecting the more or less newbie player.
Now with alliance fleets protecting on higher powers, this does mean it would even the odds a bit, as usually the attacker has the advantage of power, coming in with more fleets... we'll see how it affects attacks in the long run.