Who among the Pāṇḍavas were for the main Kurukṣetra war and who were against it?
What were their reasons for supporting or not-supporting?
What about Draupadī? Did she support the war? What were her reasons?
When DhritarAshtra denied the kingdom to PAndava due to insistence of Duryodhana, majorly they still remained hopeful for peace negotiation. They did lower down their requirements, from full Indraprastha to just 5 villages/towns. Here is the summary from Udyoga Parva of their views, before Krishna went for peace talks.
1. Yudhishtira -- Peace
Yudhishthira said, "... moved by avarice and a sinful heart, Dhritarashtra seeketh to make peace with us without giving us back our kingdom. Indeed, at Dhritarashtra's command we spent twelve years in the woods and one additional year in concealment, well-believing, O lord, that Dhritarashtra would abide firmly by that pledge of ours. That we did not deviate from our promise is well-known to the Brahmanas who were with us. The covetous king Dhritarashtra, is now unwilling to observe Kshatriya virtues. What can be more sorrowful, O Janardana, than this, that I am unable to maintain my mother and my friends? ... we said, five villages or towns, O sire, where we five may dwell in union, for we do not desire the destruction of the Bharatas.
2. Bhima -- Peace
Even Bhima, who was an arch nemesis of Duryodhana, also got polite; very unusual to his personality. Later Krishna laughs off, seeing him in such state & awakens his real self.
Bhima said, 'Speak thou, O slayer of Madhu, in such a strain that there may be peace with the Kurus. Do not threaten them with war. Resenting everything, his wrath always excited, hostile to his own good and arrogant, Duryodhana should not be roughly addressed. Do thou behave towards him with mildness... O Krishna, let the aged Grandsire and the other counsellors of the Kurus be asked to bring about brotherly feelings between brothers and to pacify the son of Dhritarashtra. Even this is what I say. King Yudhishthira also approveth of this, and Arjuna too is averse to war, for there is great compassion in him.
3. Arjuna -- Peace
Arjuna also sensed that Krishna is unable to foresee any peace with Kuru-s. Hence Arjuna's tone was more explanatory from Krishna's POV. His primary opinion was peace, but he was also OK, if Krishna wanted war.
Arjuna said, 'O Janardana, Yudhishthira hath already said what should be said. But, O chastiser of foes, hearing what thou hast said, it seemeth to me that thou, O lord, does not think peace to be easily obtainable either in consequence of Dhritarashtra's covetousness or from our present weakness. Thou thinkest also that human prowess alone is fruitless, and also that without putting forth one's prowess one's purposes cannot be achieved. What thou hast said may be true, but at the same time it may not always be true. Nothing, however, should be regarded as impracticable. It is true, peace seemeth to thee to be impossible in consequence of our distressful condition, yet they are still acting against us without reaping the fruits of their acts. Peace, therefore, if properly proposed, O lord, may be concluded. O Krishna, strive thou, therefore, to bring about peace with the foe... Whether it be peace or war with the foe that thou wishest, any wish, O Krishna, that thon mayest entertain, will certainly be honoured by us.
In fact, Arjuna remained double minded, until the first day of the actual war itself:
BG 1.36-1.39, 1.45, 2.6 - O Janardana, what happiness shall we derive by killing the sons of Dhrtarastra? Sin alone will accrue to us by killing these felons. Therefore, it is not proper for us to kill the sons of Dhrtarastra who are our own relatives. For, O Madhava, how can we be happy by killing our kinsmen? O Janardana, although these people, whose hearts have become perverted by greed, do not see the evil arising from destroying the family and sin in hostility towards, friends, yet how can we who clearly see the evil arising from destroying the family remain unaware of (the need of) abstaining from this sin? Better for me if the sons of Dhṛtarāṣṭra, weapons in hand, were to kill me unarmed and unresisting on the battleﬁeld. We do not know this as well as to which is the better for us, (and) whether we shall win, or whether they shall conquer us. Those very sons of Dhrtarastra, by killing whom we do not wish to live, stand in confrontation.
4 Nakula -- Neutral
He rather left the ball in Krishna's court. Either war or peace, he was ok with both the scenario practically.
Nakula said, .. As regards my own opinion, O hero, thou hast repeatedly expressed it, Hearing first what the wishes of the enemy are and disregarding all, do what thou regardest to be proper for the occasion. ... Persons, therefore, in this world, O foremost of men, cannot stick to the same opinion throughout. While we were living in the woods, our hearts were inclined towards a particular course of action. While we were passing the period of concealment, our wishes were of one kind, ... while we wandered in the woods, attachment for the kingdom was not so great as now.
5. Sahadeva -- War
According to him, Krishna should stick to his original plan of "provocation" disguised as "peace maker". The war must happen.
Sahadeva said, 'What hath been said by the king is, indeed, eternal virtue, but thou, O chastiser of foes, shouldst act, in such a way that war may certainly happen. Even if the Kauravas express their desire for peace with the Pandavas, still, O thou of Dasarha's race, provoke thou a war with them....
6. Draupadi -- War
Draupadi seconded with Sahadeva & wanted the revenge for her personal insult.
Drupada's daughter Krishna, of long black tresses, afflicted with great grief, applauding Sahadeva ... When they are no longer amenable to this arts of conciliation, it is not proper, O slayer of Madhu, that thou shouldst show them mercy ... O Janardana, that sin is incurred in slaying one that deserveth not to be slain. So there is equal sin in not slaying one that deserveth to be slain. ... if thou hast any compassion for me, let thy wrath, O Krishna, be directed towards the sons of Dhritarashtra.
7. Krishna -- War
Krishna's peace treaties were actually covering an intent of provocation to Duryodhana and making the other kings aware about the injustice happening. This was also noted in BR Chopara episode. The main objective of being "peace ambassador" was to show the world, that 'we are not the one who are asking for the war.'
According to Krishna, Duryodhana must be isolated by everyone, after seeing all his wrongdoings. Those supporting him, also deserve deaths.
Krishna to Yudhisthira -- ... upon being censured by all the kings of the earth, he felt no shame! He whose character is so abominable may easily be destroyed even like a rootless tree standing erect on a single weak root. The sinful and evil-minded Duryodhana deserveth death at the hands of every one, even like a serpent. ... And hearing me speak beneficial words, pregnant with virtue and profit, the rulers of various realms will regard thee as possessed of a virtuous soul, and as a speaker of truth, while at the same time, they will understand how Duryodhana is actuated by avarice. I will also tell the vice of Duryodhana, ... And as thou askest for peace no one will charge thee sinful, while all the chiefs of the earth will censure the Kurus and Dhritarashtra; and when Duryodhana will be dead in consequence of his being forsaken by all men, there will be nothing left to do. Do then what should now be done. Going unto the Kurus, I shall strive to make peace without sacrificing thy interests, and marking their inclination for war and all their proceedings, I will soon come back, O Bharata, for thy victory. I think war with the enemy to be certain.
Krishna to Draupadi -- Soon wilt thou, O Krishna, behold the ladies of Bharata's race weep as thou dost. Even they, O timid one, will weep like thee, their kinsmen and friends being slain. They with whom, O lady, thou art angry, have their kinsmen and warriors already slain. With Bhima and Arjuna and the twins, at Yudhishthira's command, and agreeably to fate, and what hath been ordained by the Ordainer, I will accomplish all this. Their hour having arrived, the sons of Dhritarashtra, if they do not listen to my words, will surely lie down on the earth turned as morsels of dogs and jackals.
8. Karna -- War
For completeness, Karna was also [morally] a PAndava, though [biologically] he was a Kaunteya.
After showing the universal form in assembly of Kaurava, Krishna chose to meet Karna & convince him to fight in side of PAndava-s for the sake of his blood relationship with them.
Even though, Karna may not be pro-war, he was obliged to fight for Duryodhana, as discussed in below post: