Not going bladebound. The campaign is centered around an airship (by my request, I've always wanted to do a game with airships, ) and my magus will be designing/wielding a gunblade.Familiar is a good arcana, I would choose that if you are not Bladebound. You might also consider Spell Blending if there are any low level wizard/sorcerer spells that you find useful. There may be better 3rd party arcana, but I am not familiar with those.
I have gone back and forth on Familiar. A hawk familiar would be pretty sweet, but according to the prd you only get the Alertness feat while your familiar is within arm's reach. So he literally has to be perched on your shoulder for you to gain the benefit, which seems kind of ridiculous.
Spell Blending may be something to look into at higher levels. Right now I've got him taking Arcane Edge (bleed damage) at mid-level, and I'm not sure how much benefit 5ish damage a round is really going to be.