2) Is the cloaks considered sacred/holy in Islam as it was worn by an Islamic prophet?
It is proven through the Hadeeth that the Companions of the Messenger, may Allah be pleased with them, sought blessings through the items of Rasulullahi salallahu 'alayhi wasallam.
This was mentioned in the Fatwa of Sahykh bin Baz rahimahullah;
Praise be to Allaah.
Seeking barakah from the relics of the Prophet (peace and blessings of Allaah be upon him) was done at the time of the Prophet (peace and blessings of Allaah be upon him), from things like the water he used for wudoo’, his garment, his food and drink, his hair and everything from him. The ‘Abbaasi (Abassid) khaleefahs and the ‘Uthmaanis (Ottomans) after them preserved the cloak of the Prophet, seeking barakah from it, especially at times of war.
Seeking blessing from things that touched his body, (peace and blessings of Allaah be upon him), such as his wudoo’, sweat, hair and so on, was something which was known to and was permissible according to the Sahaabah (may Allaah be pleased with them), and those who followed them in truth, because of the goodness and barakah that are to be found in that. The Prophet (peace and blessings of Allaah be upon him) approved of this.
http://www.islam-qa.com/en/ref/10045
Hope it helps answer your question. :)