Early imami shias and the source of Islamic knowledge of the infallibles

Synopsis: This post briefly outlines the beliefs of the early Shias such as Yunus b. Abdur Rahman, Shaikh Ibn al Junaid and the early Qummi scholars regarding the source of knowledge of the Imams for Islamic laws.

"The shia subsects" by Shaikh Sa'd b. Abdullah al Ash'ari al Qummi, Page 98 (original Arabic page posted at the bottom of the post)

"They believe that the Imam (as) obtains his knowledge from the notes of his father, and the knowledge he inherits about the general and specific Islamic laws. And some of these sects believe that it is permissible for the Imam (as) to exercise Qiyas to deduce Islamic laws. They assume that qiyas is permissible for the messengers, prophets and the Imams. Yunus b. Abdur Rahman used to say that: 'The Messenger of Allah (swt) used to derive and deduce [Islamic laws] based on what was revealed to him [instead of only conveying what was revealed], and this practice overall cannot be accused of being qiyas.' So basically they believed that it is permissible for the Imam (as) to exercise qiyas based on his principles, as he is an infallible who is not prone to slips and errors so will not be mistaken in qiyas."

المسائل السروية - الشيخ المفيد - الصفحة ٧٥

"Masail as sarawiyah" by Shaikh Mufid, Page 75

وأجبت (6) عن المسائل التي كان ابن الجنيد جمعها وكتبها إلى أهل مصر، ولقبها ب‍ (المسائل المصرية) وجعل الأخبار (7) فيها أبوابا، وظن أنها مختلفة في معانيها، ونسب ذلك إلا قول الأئمة عليهم السلام فيها بالرأي

And I have replied about the Islamic issues that Shaikh Ibn al Junaid wrote for the people of Egypt, and entitled the book "Masail al Misriyah" and recorded ahadith of the Imams (as) in it in chapters, and thought that they differ in meaning due to the Imams having issued them by their opinion.

"Tashihul itqadat" by Shaikh Mufid, Page 135

وقد وجدنا جماعة وردوا إلينا من قم يقصرون تقصيرا ظاهرا في الدين ، وينزلون الأئمة - عليهم السلام - عن مراتبهم ، ويزعمون أنهم كانوا لا يعرفون كثيرا من الأحكام الدينية حتى ينكت في قلوبهم ، ورأينا من يقول إنهم كانوا يلتجئون 
في حكم الشريعة إلى الرأي والظنون

We came across a group of scholars from Qum who were committing open taqsir in religion and down grading the Imam (as) from their position. They believed that the Imam (as) do not know many of the rulings for Islamic laws until it is inspired in their hearts [by Allah]. And we even saw them say that the Imams (as) resort to their opinions and speculations in Islamic laws.

"Firaq al Shia" (also known as "al maqalat wal firaq") by Shaikh Sa'd al Qummi, Page 98