Grading: (1) This hadith is "hasan li-ghayrihi" (good due to supporting evidence), and there is "no harm" in the narrators of this chain.
Technical note / Defect ('illah): However, it is "mursal" and contains the "'an'anah" of al-Mubarak bin Fadalah. It is, however, narrated through several other routes from al-Hasan (al-Basri), yet the "irsal" remains. Something similar is narrated as "mursal" from Muhammad bin al-Munkadir and as "munqati'" from Sa'id bin 'Abd al-'Aziz al-Dimashqi, and the narrators of both are trustworthy. So by the combination of all these routes the report rises to the level of "hasan" (in sha' Allah).

Reference / Source: It was narrated by Abu Bakr al-Khallal in "al-Sunnah" (345) and Ibn 'Asakir (25/473) through the route of Waki' bin al-Jarrah, from al-Mubarak bin Fadalah, with this chain.

Reference / Source: It was narrated by Ibn Abi Shaybah (12/135) through the route of Yunus bin 'Ubayd; by Ahmad in "Fada'il al-Sahabah" (1283), Ya'qub bin Sufyan in "al-Ma'rifah wa al-Tarikh" (11/488) and Ibn 'Asakir (25/473) through the route of Ziyad al-A'lam; and by Ahmad in "al-Fada'il" (1283) through the route of Humayd al-Tawil. All three (Yunus, Ziyad and Humayd) narrate from al-Hasan al-Basri. Likewise Ibn 'Asakir (25/473) narrated something similar as a "mursal" of Muhammad bin al-Munkadir, with a chain whose narrators are trustworthy.

Reference / Source: Likewise (25/473) something similar is narrated from Sa'id bin 'Abd al-'Aziz al-Dimashqi, who attributed it to the Prophet (marfu').
Grading: Sa'id is one of the followers of the Successors, so despite the trustworthiness of its narrators it is "mu'dal".