Below you would see quotes with 3 different chains from shia imams, that all companions except 3 or 4 from them, apostated after death of prophet (sallalahu alaihi wa ala alihi wa sallam).
All of them from shia book “Ihtiyar marifatul Rijal” of sheikh Tusi.
From Hannan ibn Sadeer from his father, from Abu Jafar (alaihi salam): “People became apostates after prophet (s) except 3 of them”. I said: “Which 3 of them?” He said: Al-Miqdad ibn al-Aswad, Abu Dharr al-Qifari, Salman al-Farisi….
عن أبي بصير، قال: قلت لابي عبد الله ارتد الناس الا ثلاثة أبو ذر وسلمان والمقداد قال: فقال أبو عبد الله عليه السلام: فأين أبو ساسان وأبو عمرة الانصاري ؟
“From Abu Baseer: I said to Abu Abdullah: “Apostated people except 3 of them: Abu Dharr, Salman and al-Miqdad”. And Abu Abdullah (alaihi salam) said: “Where are Abu Sasan and Abu Amrah al-Ansare?”
What is obvious from text imam didn’t reject idea that all people apostated after death of the prophet (sallalahu alaihi wa ala alihi wa sallam). He simply added 2 other names.
From Abu Bakr al-Hadrami: Abu Jafar said: People apostated except 3 of them: Salman, Abu Dharr and Miqdad.