I agree that Buddha and Arahant also subject to their previous Karma. For example Buddha got injured when Devadatta though a stone at him. One Arahant was beaten to death by thieves.
I think that Arhant do not accumulate fresh kamma so it is inaccurate to say Arhant will have residue of human defilement.
The 2 aspects of Nibbāna are:
1: The full ceasing of defilements kilesa
-parinibbāna also called sa-upādi-sesa-nibbāna see: It. 41, i.e. 'Nibbāna with the groups of existence still remaining' see: upādi. This takes place at the attainment of Arahatship, or perfect Nobility see: ariya-puggala.
2: The full ceasing of the groups of existence khandha-parinibbāna also called an-upādi-sesa-nibbāna see: It. 41, A. IV, 118, i.e. 'Nibbāna without the groups remaining', in other words, the coming to rest, or rather the 'no-more-continuing' of this physico-mental process of existence. This takes place at the death of the Arahat. - App.: Nibbānahttp://what-buddha-said.net/library/Bud