Although we have written about the standpoint of the Shia regarding the Sahabah and explained it thoroughly on this website, nevertheless, we intend to shed some light on a few points that can be found in the question above:

1-Shias have been falsely accused of disrespecting and discrediting the Sahabah which isn't true; the Shia have always followed the path of the Ahlul-Bayt in respecting them, this saying of Imam Ali being good confirmation of such a claim: “I have seen the companions of the Prophet but I do not find anyone resembling them. They began the day with dust on the hair and face (in hardship of life) and passed the night in prostration and standing in prayers. Sometimes they put down their foreheads and sometimes their cheeks. With the recollection of their resurrection it seemed as though they stood on live coal. It seemed that in between their eyes there were signs like knees of goats, resulting from long prostrations. When Allah was mentioned their eyes flowed freely till their shirt collars were drenched. They trembled for fear of punishment and hope of reward as the tree trembles on the day of stormy wind.[1]

2- As for what you said about Quranic verses, the Quran says:

a) “وَ مِمَّنْ حَوْلَکُمْ مِنَ الْأَعْرابِ مُنافِقُونَ وَ مِنْ أَهْلِ الْمَدِینَةِ مَرَدُوا عَلَى النِّفاقِ لا تَعْلَمُهُمْ نَحْنُ نَعْلَمُهُمْ سَنُعَذِّبُهُمْ مَرَّتَیْنِ ثُمَّ یُرَدُّونَ إِلى‏ عَذابٍ عَظِیمٍ‏”[2]

b) “وَ ما مُحَمَّدٌ إِلَّا رَسُولٌ قَدْ خَلَتْ مِنْ قَبْلِهِ الرُّسُلُ أَ فَإِنْ ماتَ أَوْ قُتِلَ انْقَلَبْتُمْ عَلى‏ أَعْقابِکُمْ وَ مَنْ یَنْقَلِبْ عَلى‏ عَقِبَیْهِ فَلَنْ یَضُرَّ اللَّهَ شَیْئاً وَ سَیَجْزِی اللَّهُ الشَّاکِرِینَ‏”[3]

c) “وَ یَحْلِفُونَ بِاللَّهِ إِنَّهُمْ لَمِنْکُمْ وَ ما هُمْ مِنْکُمْ وَ لکِنَّهُمْ قَوْمٌ یَفْرَقُونَ”[4]

d) “لَقَدْ کانُوا عاهَدُوا اللَّهَ مِنْ قَبْلُ لا یُوَلُّونَ الْأَدْبارَ وَ کانَ عَهْدُ اللَّهِ مَسْؤُلًا”[5]

e) “عَفَا اللَّهُ عَنْکَ لِمَ أَذِنْتَ لَهُمْ حَتَّى یَتَبَیَّنَ لَکَ الَّذِینَ صَدَقُوا وَ تَعْلَمَ الْکاذِبِینَ‏”[6]

f) “.  لَمْ تَرَ إِلَى الَّذِینَ قِیلَ لَهُمْ کُفُّوا أَیْدِیَکُمْ وَ أَقِیمُوا الصَّلاةَ وَ آتُوا الزَّکاةَ فَلَمَّا کُتِبَ عَلَیْهِمُ الْقِتالُ إِذا فَرِیقٌ مِنْهُمْ یَخْشَوْنَ النَّاسَ کَخَشْیَةِ اللَّهِ أَوْ أَشَدَّ خَشْیَةً وَ قالُوا رَبَّنا لِمَ کَتَبْتَ عَلَیْنَا الْقِتالَ لَوْ لا أَخَّرْتَنا إِلى‏ أَجَلٍ قَرِیبٍ”[7]

g) “کَما أَخْرَجَکَ رَبُّکَ مِنْ بَیْتِکَ بِالْحَقِّ وَ إِنَّ فَرِیقاً مِنَ الْمُؤْمِنِینَ لَکارِهُونَ یُجادِلُونَکَ فِی الْحَقِّ بَعْدَ ما تَبَیَّنَ کَأَنَّما یُساقُونَ إِلَى الْمَوْتِ وَ هُمْ یَنْظُرُونَ وَ إِذْ یَعِدُکُمُ اللَّهُ إِحْدَى الطَّائِفَتَیْنِ أَنَّها لَکُمْ وَ تَوَدُّونَ أَنَّ غَیْرَ ذاتِ الشَّوْکَةِ تَکُونُ لَکُمْ وَ یُرِیدُ اللَّهُ أَنْ یُحِقَّ الْحَقَّ بِکَلِماتِهِ وَ یَقْطَعَ دابِرَ الْکافِرِینَ لِیُحِقَّ الْحَقَّ وَ یُبْطِلَ الْباطِلَ وَ لَوْ کَرِهَ الْمُجْرِمُونَ”[8] So there was a group of believers who weren’t content with accompanying the prophet (pbuh) in jihad.

h) “وَ یَسْتَأْذِنُ فَرِیقٌ مِنْهُمُ النَّبِیَّ یَقُولُونَ إِنَّ بُیُوتَنا عَوْرَةٌ وَ ما هِیَ بِعَوْرَةٍ إِنْ یُرِیدُونَ إِلَّا فِرارا”[9]

i) “یا أَیُّهَا الَّذِینَ آمَنُوا ما لَکُمْ إِذا قِیلَ لَکُمُ انْفِرُوا فِی سَبِیلِ اللَّهِ اثَّاقَلْتُمْ إِلَى الْأَرْضِ أَ رَضِیتُمْ بِالْحَیاةِ الدُّنْیا مِنَ الْآخِرَةِ فَما مَتاعُ الْحَیاةِ الدُّنْیا فِی الْآخِرَةِ إِلَّا قَلِیلٌ”[10] This is while the verse is addressing those who don’t want to go to jihad with the phrase “یا ایها الذین آمنوا” which shows that it is the believers who are being addressed, not anyone else, we also know that Allah (swt) threatened those who wouldn’t go out for jihad and would bring excuses like the weather being too hot, with the phrase “قُلْ نارُ جَهَنَّمَ أَشَدُّ حَرًّا لَوْ کانُوا یَفْقَهُونَ”[11]

j) “وَ لَوْ أَرادُوا الْخُرُوجَ لَأَعَدُّوا لَهُ عُدَّةً وَ لکِنْ کَرِهَ اللَّهُ انْبِعاثَهُمْ فَثَبَّطَهُمْ وَ قِیلَ اقْعُدُوا مَعَ الْقاعِدِینَ لَوْ خَرَجُوا فِیکُمْ ما زادُوکُمْ إِلَّا خَبالًا وَ لَأَوْضَعُوا خِلالَکُمْ یَبْغُونَکُمُ الْفِتْنَةَ وَ فِیکُمْ سَمَّاعُونَ لَهُمْ”[12]

As can be seen, these verses apply to the followers and the Sahabah of the prophet more than anyone else. Therefore no one can claim that every individual who has seen the prophet even for a moment is considered righteous. The truth of the matter is that in order to justify the tyranny and corruption of the Umayyid dynasty, some have tried to use theories like these and say that as long as a person is of the Sahabah, he is righteous. But according to the Shia standpoint on the issue, according to the Quran not all the Sahabah were totally righteous, but were of different levels of righteousness, for the Quran has stated that there were liars, hypocrites, sinners, ones who didn’t agree with the prophet regarding jihad, those who were too sluggish to go to war, those who didn’t believe in the prophet (pbuh), and those who preferred not to go out to war (a group of believers that weren't pleased to go out and confront the enemy and were sluggish in executing this task) among the Sahabah[13], and as was said before, these verses address these believers with the phrase of “ یا ایها الذین آمنوا”.

It is also incorrect to categorize the prophet’s (pbuh) followers and Sahabah into only two categories; those who were completely righteous and total hypocrites, knowing that there may be many of them who were merely sinners and as we all know, one doesn’t become a hypocrite just by sinning. In other words, one must distinguish between the sinner and the hypocrite; there is a great difference between the two.

3- It was said that all hypocrites were known from the true believers by the end of the first or second year of Islam's advent and Muslims were able to distinguish between the true believers and hypocrites. First of all, hypocrisy isn't a temporary concept that ends easily; it may remain till the Day of Judgment and there might be hypocrites till then. Secondly, the prophet (pbuh) had shown his fear of those who were close and around him.  There is a hadith in the books of our Sunni brothers that when the verse "بلغ ما أنزل إلیک من ربک"  was revealed the prophet said: “What can I do knowing that I am alone and people will unite against me?!” Then this verse was revealed"وإن لم تفعل فما بلغت رسالته".[14]

Surely this fear was not of the disbelievers because there were none for the prophet (pbuh) to convey Allah's (swt) message to on the day of Ghadir on the tenth year after hijrah. If those around the prophet (pbuh) were actually devout companions of his, then what was the reason for him saying: «انما أنا واحد، کیف اصنع یجتمع علی الناس»؟[15] What reason would there be for him to be so afraid of the message not getting through to the people?

4-There are verses in the Quran such as: "وَ ما مُحَمَّدٌ إِلَّا رَسُولٌ قَدْ خَلَتْ مِنْ قَبْلِهِ الرُّسُلُ أَ فَإِنْ ماتَ أَوْ قُتِلَ انْقَلَبْتُمْ عَلى‏ أَعْقابِکُمْ وَ مَنْ یَنْقَلِبْ عَلى‏ عَقِبَیْهِ فَلَنْ یَضُرَّ اللَّهَ شَیْئاً وَ سَیَجْزِی اللَّهُ الشَّاکِرِینَ‏"[16]   that not only show that not all the Sahabah were righteous but also that some had even denounced their faith.[17]

5- The inquirer must also note that the history of that time shows very clearly that some of the Sahabah like Mughayra and Walid[18] and others belonging to the Mareghin, Qasetin and Nakethin (the three groups that rioted against Imam Ali during his reign and went to battle against him) had committed adultery and murder.

It is on this basis that Shafe’i says that the testimony of 4 individuals isn't accepted and has no credit: Muawiya, Amr ibn Aas, Mughayra and Ziyad (because none were trustworthy and reliable).[19]

Another proof that confirms what we say is that even some of the Sahabah did not consider other Sahabah to be righteous and would sometimes even accuse them of being hypocrites.[20]