Mistakes in Potter novels

Can anyone plz explain:

Barty Crouch Jr. comes to Hogwarts disguised as Moody.His only intention is to send harry to that graveyard so that wormtail brings back voldy.He makes the cup a portkey and succeeds in his mission.What i dont understand is why didnt he make any other object a portkey(a pot,pen etc.), call harry to his room and hand that portkey to him?Why making it so long and complex?

 

Book6

At last, when d death eaters were talking to a wandless dumbledore, why didnt dumbledore disapparate?I know u cant disapparate inside Hogwarts but he cud have lifted the enchantment d way he did during the apparition lesson?I dont think u need a wand to either cast an enchantment or disapparate?

 

Does sumone has an explanation?