Well, let me see if I can help.
1 - I don't think you power it up through Airbus sockets.
2 - Any B2 LAME will be able to do the rewiring work for you.
3 - Really just a matter of chosing the wire type you want. If you plan on listening to mp3, high purity copper is advisable, but more prone to corrosion than allumel/alluminium types. An inverter relay will give you the chance of switching from A/C sockets or mp3 for listening. Or no relay, if you want to mix both sources. Just make source's output impedance is at least 100 times greater than your phones.
Hope I have been of some help.
