To what extent are the hadiths valid that speak of reciting the opening and concluding verses of Surat Al-Baqarah at the grave, which were narrated from Abdur-Rahman ibn Al-Ala' from his father and from Abdullah ibn Umar, and is what was reported regarding the ruling of some imams on them as being "hasan" (good) or that their narrators are trustworthy, correct?

The hadith that recommends reciting the opening (Fatihah) and concluding verses of Surat Al-Baqarah at the head of the deceased in the grave is weak in its chain of narration (isnad). It was reported by Al-Tabarani and Al-Bayhaqi with weak chains, which include unknown or weak narrators.

As for what is authentically reported from the Prophet, peace be upon him, when placing the deceased in the grave, it is the saying: "In the name of Allah and by Allah, and according to the religion of the Messenger of Allah," as narrated by Al-Tirmidhi and authenticated by Al-Albani.