Are Flying units defeated when Horizon's Wrath pull the plank?

Buccaneer's Pistoleer talent says that it loses an upgrade when it attacks using Pistoleer, but minions normally cannot get upgrades. Is this a typo?

Can Horizon's Wrath cannonballs hit the Greige fortress?

Can Mistbane use Swashbuckler and Pistoleer at the same time?

Can Tinbeard attack with Pistoleer against an adjacent unit to flip?