What is the authenticity of what was narrated from Sufyan al-Thawri and al-Hasan al-Basri regarding the permissibility of looking at the adornment of Dhīmmī women, and what is the authenticity of the statement permitting looking at the hair of a disbelieving woman?

It is narrated in Sahih al-Bukhari that Al-Hasan al-Basri said to Sa'id ibn Abi al-Hasan, when the latter mentioned that non-Arab women uncover their chests and heads: "Avert your gaze from them," citing the verse: "Say to the believing men that they cast down their gaze and guard their private parts." The two narrations from Al-Thawri and Al-Hasan al-Basri have not been judged as authentic or weak; scholars mention them in the context of discussing the Muslim woman's hijab, the awrah (private parts) of a free woman and a slave woman, and the ruling on looking at a slave woman, all of which are ancient matters of disagreement.