Oh thankyou for the reply.
I completely agree the pointers you made. The daughters in those days were important only if they married someone important or gave birth to someone important. Draupadi was the only exception in this case, else we never even got to know the real name of Madri who even performed Sati on her husband's pyre, something which was so good in Sanatani society according to leftist historians. Had Nakul Sahdev done something better we have at least got to know her real name.
Coming to the children of Duryodhan maybe his second wife didn't have any children or else had only daughters who didn't marry anyone important. Because if he would have had sons, they too would have been mentioned like Karna's sons. Because if you exclude Vrishsena, the other sons of Karna were nothing better than Lakshman. They were pretty ordinary warriors. Still them finding a mention over the sons of Duryodhan (if there were more) seems improbable to me unless Duryodhan didn't get them to the war. And I guess had that been the case then too they would have been mentioned to show how cowards Duryodhan was to save his sons while causing deaths and destruction of others
There is a fanfiction drama on Duryodhan called Urubhangam. It is supposed to have been written by Bhasa in the fourth or fifth century AD. That has another son of Duryodhan mentioned. This as I told you being from the perspective of Duryodhan had many inaccurate things. In fact to give somehow a happy ending like in Sanskrit plays, they have made Ashwathama successful in killing the Pandavas on 18th night. Duryodhan dies after hearing this news in happiness and then his son ascends the throne. Well not sure if this son was completely fictional and his imagination or back then he had access to some other Mahabharata versions where one son of Duryodhan survived the war. Being 5th century it's before the invasions in India so probably by then not many of our books would have been burnt. We can't rely on his narration, but still I don't feel like his creation is completely worth ignoring because despite being pro Duryodhan the play didn't glorify Duryodhan like Ajaya and kept his actions and facts intact excluding the ending, I don't think he would have added a fictional character.
Thankyou for the citation of 350 wives. I sometimes now think that having huge number of wives was something like status symbol. Otherwise why the wives were always in round figures like 16000, 350 etc.(for those with more than 10 wives). Just to explain how much righteous and mighty a person was, they made him have many wives. The numbers probably are poetic exaggerations. Completely my view