A 721
Yes to all of the above. Positive energy is magical and a positive-dominant plane would affect incorporeal creature not protected from it the same as corporeal ones.
A 733
Versatile Combatant, from Drow of the Underdark, will keep you from provoking AoOs when attacking with a Hand Crossbow.
A 734
No. The eyestalks are still part of the same spellcaster.