I did think I wrote clearly about the shlokas, 4, 5, and 6. But some people thought that it was not very clear. So I would like to clarify. Let me take an example of we trying to wake up early in the morning to do meditation. On one side we want to do it ,so as to improve our 'chances'of achieving some level of 'samadhi'.but then we don't want to get out of 'bed' and want to continue sleeping . In this 'fight ' we will have 2 sides , so when our mind (it's son, which is thought. )looks at 'both ' sides of this fight , it will realise that the devote had done the study of scripture, has changed his life and tells the Truth, does not do hoarding, has celibacy, does follow nonviolence, control of breath(pranayam), etc ,So when one looks at the different names that are taken by Duryodhan, we see all this ' names' reflecting how we 'prepare ' for the samadhi.
Now fof the shloka ,7 and 8. In this one (8) he talking about who are going to 'fight ' from side of the 'mind '.They are Drona , Bhishma, Karna , Kripa, Ashwatthama,Vikarna-son of Son of Somadatta, and Jayadratha.
As I stated before Drona represents the Saunskara or impressions from past lives. So naturally they will 'guide ' us in doing good things or bad things--habits. Most of is have more bad habits than good , so they will 'side ' on the side of mind and not intellect. So Drona went on side of Duryodhana .We also know that Bishma represents the 'Ego ' . The ego is nothing other than 'self ' attached to the body. So as long as it thinks that it is physical body , it will side on the side of the body , it's pleasure and the mind , which is looking for the same . i.e. the bodily pleasures.So Duryodhana is looking to Drona and Bishma for the help. Bhishma also represents the Asmita- which what makes us feel -"I AM ".
Now about the other names
Kripa- This according to Yoganand is the Avidya. ( how this is derived is difficult to explain, but to summarise, root krip to klrip--which means imagine--one who has false understanding of the matter. This is the MAYA .
Karna--This means ' one who behaves and performs the actions that gives pleasure. 'Even though Karna was born of Kunti (power of dispassion ) and SUN , he was born before Kunti was united with the intellect or discrimination. So he was under the influence of the mind and so preferred the actions that would give bodily pleasure.
Vikarna is repulsion or the Dwesha.
Jyadratha--is Abhiniwesh. We have several attachments, to eat good food to listen to pleasing music or words, to take stimulants etc , But our greatest attachment is to our body and desire to 'live' This is strongest desire and that is the attachment to the body , no matter how old and disease ridden or painful it is .
Son of Somadatta (Bhurishravas),This one represents the action that we do for the material things . So even though this is also action it is done for the purpose of material pleasure and so it is under control of Mind and Ego .
Ashwatthama-- He is the son of the Drona and represents the latent desire. Drona is sauskara, may be the tendencies that are going to guide us now , while the Ashwatthama is latent tendencies or desires , that is why he is 'immortal ' . i.e. the latent desires do not die .