Are twelve hypocrite companion of prophet (SAWW) known?

Question

According to below hadith there are twelve hypocrite among companions of prophet.

Are they known after 1400 years? Indeed such Sahaba can not be a trusted source as narrators of hadith and it is useful to we know them for distinguishing fabricated hadith from authentic hadith really said by prophet. when a hypocrite said : I hears prophet SAWW said so and so, it can not be trusted. what we should do if we find out some of famous Sahaba we highly regarded them until know were in fact hypocrites? can Muslims defending them frankly admit it and change their beliefs about them?

I said to 'Ammar: What is your opinion about that which you have done in case (of your siding with Hadrat 'Ali)? Is it your personal opinion or something you got from Allah's Messenger (may peace be upon him)? 'Ammar said: We have got nothing from Allah's Messenger (may peace be upon him) which people at large did not get, but Hudhaifa told me that Allah's Apostle (may peace be upon him) had especially told him amongst my Companion, there are twelve hypocrites out of whom eight would not get into Paradise, until a camel would be able to pass through the needle hole. The ulcer would be itself sufficient (to kill) eight. So far as four are concerned, I do not remember what Shu'ba said about them.

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَسْوَدُ بْنُ عَامِرٍ، حَدَّثَنَا شُعْبَةُ بْنُ الْحَجَّاجِ، عَنْ قَتَادَةَ، عَنْ أَبِي نَضْرَةَ، عَنْ قَيْسٍ، قَالَ قُلْتُ لِعَمَّارٍ أَرَأَيْتُمْ صَنِيعَكُمْ هَذَا الَّذِي صَنَعْتُمْ فِي أَمْرِ عَلِيٍّ أَرَأْيًا رَأَيْتُمُوهُ أَوْ شَيْئًا عَهِدَهُ إِلَيْكُمْ رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ مَا عَهِدَ إِلَيْنَا رَسُولُ اللَّهِ صلى الله عليه وسلم شَيْئًا لَمْ يَعْهَدْهُ إِلَى النَّاسِ كَافَّةً وَلَكِنْ حُذَيْفَةُ أَخْبَرَنِي عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏ "‏ فِي أَصْحَابِي اثْنَا عَشَرَ مُنَافِقًا فِيهِمْ ثَمَانِيَةٌ لاَ يَدْخُلُونَ الْجَنَّةَ حَتَّى يَلِجَ الْجَمَلُ فِي سَمِّ الْخِيَاطِ ثَمَانِيَةٌ مِنْهُمْ تَكْفِيكَهُمُ الدُّبَيْلَةُ وَأَرْبَعَةٌ ‏"‏ ‏.‏ لَمْ أَحْفَظْ مَا قَالَ شُعْبَةُ فِيهِمْ ‏.‏

http://www.sunnah.com/urn/372500

Answer 1

There are indirect ways that the Muslims knew who is the Munafiq

It was narrated that 'Abdullah bin 'Umar said:

When 'Abdullah bin Ubayy died, his son came to the Prophet and said: 'Give me your shirt so that I may shroud him in it, and (some and) offer the (funeral) prayer for him, and pray for forgiveness for him'. So he gave him his shirt then he said: 'When you have finished, inform me and I will offer the (funeral) prayer for him.' But 'Umar stopped him and said: 'Hasn't Allah forbidden you to offer the (funeral) prayer for the hypocrites?' He said: 'I have two options. Whether you ask forgiveness for them (hypocrites) or ask no forgiveness for them." So he offered the (funeral) prayer for him. Then Allah, Most High, revealed: 'And never pray (funeral prayer) for any of them (hypocrites) who dies, nor stand at his grave.' So he stopped offering the (funeral) prayer for them."

(Sahih)

Another way:

‘Abd-Allaah ibn ‘Umar (may Allaah be pleased with him) said:

When we noticed that a man was not present at Fajr and ‘Isha’ prayer, we would think badly of him

Narrated by al-Haakim in al-Mustadrak, 764, and elsewhere; he classed it as saheeh according to the conditions of the two shaykhs (al-Bukhaari and Muslim), and al-Dhahabi and al-Albaani agreed with him.

because in the hadith it says:

Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah (PBUH) said,

No Salat is more burdensome to the hypocrites than the Fajr (dawn) prayer and the 'Isha' (night) prayer; and if they knew their merits, they would come to them even if they had to crawl to do so."

[Al-Bukhari and Muslim]

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Direct way :

By Hudhayfah ibn al-Yaman, since of Hudhayfah's ability to keep a secret, Muhammad told him the names of the hypocrites. Hudhayfah was called The Keeper of the Secret of the Messenger of Allah, remaining faithful to his pledge of secrecy.

After Muhammad's death, the Khalifah(Umar) often sought his advice concerning their activities but he remained tight-lipped. Umar was only able to find out indirectly who the hypocrites were by monitoring Hudhayfah’s attendance at the funeral prayer following the death of a Muslim. If Hudhayfah did not attend Umar refrained from performing the funeral prayer for that person.

Once Umar asked Hudhayfah if he(Umar) was Munafiq. and he said No!! then he said I will not answer anyone else more if they asked me the same question.