EDIT 2: I thought that perhaps I could cast Mage Armour on Hal, since his armour has no effect on his AC when he's in wild shape, but it won't cast because he "Can't have armour equipped". So that's somewhat problematic. Not sure if anyone else has picked up on that before.
I've been thinking about this again, and I might actually switch Hal out of armour and into one of the clothing items so that Mage Armour will work on him. Since he's almost always wild-shaped for me, it seems more strategic. Not sure if others have experimented with this?