question #3 Sahih Muslim 954a, Book 11, Hadith 89 : Who is considered a reliable source for narrating hadiths in this context?

I said to Sha’bi: Who narrated it to you? He said: An authentic one, ‘Abdullah b. ‘Abbas. This is the word of a hasan hadith. In the narration of Ibn Numair (the words are): The Messenger of Allah (ﷺ) went to the grave which had been newly prepared and prayed over it, and they also prayed who were behind him and he recited four takbirs. I said to ‘Amir: Who narrated it to you? He said: An authentic one who saw him, i e. Ibn ‘Abbas.