How a sentient weapon becomes a patron would you mind giving an example?

Having trouble grasping how a sentient weapon becomes a patron would you mind giving an example? Should Hexblade be a pact?

What is the CR for a Tiny Servant in Xanathar’s?

What is the familiar sitting on the War Mage’s shoulder?

Can Aasimar take human feats?

Would a half drow be able to take the drow high magic feat from Xanathar’s Guide?

Curving Shot: can be used every round cause all arrows can be considered magical by 7th level?

Dragon Hide feat + Barbarian oes the unarmored defense Con bonus stack with the feat’s natural AC 13?