Khalid ibn Sinan
Reagrding your first question: Khalid ibn Sinan al-`Abasi. There is a sound but mursal report from Ibn `Abbas that his daughter -- or descendent -- came to see the Prophet, Allah bless and greet him, and he said: "Welcome to the daughter of a prophet whom his own people lost (through their lack of faith)." Narrated by Ibn Kathir in al-Bidaya (al-Ma`arif ed. 2:211), Ibn Hajar in al-Isaba (2:370-371), Ibn Sa`d in al-Tabaqat (1:295) and others. But the Prophet -- Allah bless and greet him -- said that there is no Prophet between him and `Isa, and this is narrated in Sahih al-Bukhari. The Fusus reconcile the two reports by stating that Khalid's prophethood was not during his life on earth, but after he died and entered Barzakh, hence it does not count in the same way as the missions of other prophets, and Allah knows best.
He should not be confused with the Companion of the same name, Khalid ibn Sinan al-Awsi who fought at Badr, may Allah be well-pleased with him. By the way, Shaykh Mohyi al-Din Ibn Arabi forbade reading his books without training in Sufi terminology. Does the person who reads his books possess such training?
I myself would like to get books from shaykh Hasan al-Saqqaf, but the only way I know is to go to Jordan and get them for oneself which I have not done so far.
Please give my salam and love to shaykh Yasser.