Are the people of Nahrawan and Dhu al-Khuwaisirah considered among the Companions, and what is the evidence for that?

A Companion (Sahabi) is one who met the Prophet as a believer and died in that state. As for the people of Nahrawan, they are not Companions. Their leader, Dhul-Khuwaisirah, despite seeing the Prophet, was a hypocrite. This is evidenced by his stance when he objected to the Prophet's division of spoils. The Prophet (peace be upon him) described him and his companions as those who recite the Quran, but it does not go beyond their collarbones, and they will abandon the religion as an arrow pierces its target and leaves it. Anas also narrated that there was a man whose devotion and diligence impressed the Companions, so they described him to the Prophet (peace be upon him). When the Prophet saw him, he said: "Indeed, in his face there is a trace of the devil." He then asked him: "I implore you by Allah, did you say when you stood before the gathering that there is no one among the people better or more excellent than me?" He replied: "By Allah, yes." The Prophet (peace be upon him) ordered his killing, but he was not killed. The Prophet said: "Had he been killed, no two men from my Ummah would have differed, he would have been the first and the last of them."