All the three Ahadith have been narrated from Dhul Joushan, father of Shimr. Being relative of a bad person does not make one bad also. Ubaydullah Bin Abbas was grandson of Imam Ali and he deserted Imam Hassan and joined Muawiyah, does that make his father untrustworthy?
And as for the saying of Bukhari, he merely speculates that Narrations have come through son of Dhul Joushan rather than directly from him.
And most importantly, one has to see the content of narration also, if it is sameas other narrations from different narrators, why should there be any problem.
Sunni Scholars Took Hadith From Shimr (L.a) (Killer of Imam Hussain a.s) ↩︎