What is the most accurate determination of the time of Al-Mas'udi's اختلاط (confusion/memory impairment), and when did Asad ibn Musa, Qurrah ibn Habib, and Zayd ibn al-Hubab hear from him, and how are his narrations distinguished?

Al-Mas'udi became confused in his later years, and the date of his confusion was in the year 157 AH or shortly thereafter. As for the three shaykhs mentioned in the question, no one has stated that they narrated from him after his confusion, nor is it clear that they narrated from him before his confusion. Therefore, their narration from him is paused until its status becomes clear.