Before encountering Esav, Yaakov split his camp as originally planned. This position subdivides regarding whether the goal was to escape from Esav or to confront him.
Flight
Yaakov divided his camp so that at least one portion of his household could flee and escape Esav's wrath.
"וַיַּחַץ אֶת הָעָם אֲשֶׁר אִתּוֹ" – Who was to be in each camp?
Family versus possessions – Abarbanel asserts that Yaakov placed his family in one camp and his possessions in the other. Akeidat Yitzchak concurs, but assumes that Yaakov had some men of war accompany each group.
Maidservants versus real wives – R. Bachya learns from Bereshit 33:2 that the maidservants and children were in one camp with some of the possessions and hired hands, while Leah and Rachel and the rest of the property were in the other.
Division of possessions only – According to R. Avraham b. HaRambam and R. D"Z Hoffmann, Yaakov only split his cattle and servants1 but kept his entire family together with him (either in a group of their own,2 or in the first camp).3
"וְהָיָה הַמַּחֲנֶה הַנִּשְׁאָר לִפְלֵיטָה" – Purpose of the division – Though all these sources assume that the word "לִפְלֵיטָה" means an escape, they differ regarding the details of Yaakov's plan:
Save family – According to Akeidat Yitzchal and Abarbanel, Yaakov was hoping that Esav would only attack the camp with his possessions, allowing his immediate family to escape.4
Save some of all – R. Bachya presents Yaakov as dividing his household more evenly, perhaps because he did not know which camp was to be attacked and did not want to risk losing all his loved ones.5 Nonetheless, he still placed those most precious to him in the second camp, assuming that they would be safer.
Save possessions – R. Avraham b. HaRambam maintains that Yaakov preferred that his loved ones all share the same fate, be it death or salvation, while R. D"Z Hoffmann asserts that he kept them close by to keep an eye over them. The division of possessions was simply an attempt to save whatever property he could.
Why send to Seir
According to Abarbanel, when Yaakov met the angels in Mahanayim (32:2-3) it was revealed to him that Esav was en route and close by. He, therefore, sent messengers to both test his brother's feelings and to let Esav know that he was not coming as a poor brother in need of alms, but as an equal.6
According to R. D"Z Hoffmann, in contrast, Yaakov was planning on visiting Esav in Seir to make up. He sent messengers to let Esav know that he was coming in good faith.
It is also possible that Yaakov had sent word to Edom (to either test the waters or appease him), but without any intention of meeting Esav face to face at this point on his journey.7 Only when he heard that Esav was approaching, did he think about a confrontation.
Esav's intentions
Fight
The rearrangement of the camp was a military strategy, meant to facilitate the expected battle against Esav.
Change of Plan
Though Yaakov originally intended to divide his camp, he changed his mind before meeting Esav. The position divides regarding the reason for the change of heart:
No Longer Necessary
After his victory over the angel/man, Yaakov no longer feared his brother and saw no need to rearrange his camp in preparation for the encounter.
"וַיַּחַץ אֶת הָעָם אֲשֶׁר אִתּוֹ" – Who was to be in each camp?
Split only non-family members – R. Avraham b. HaRambam asserts that Yaakov divided his possessions and larger household into two camps but that he kept his wives and children with him, distinct from both.8 He preferred that they either all survived or all perished together.
Possessions split, children not – According to Netziv, Yaakov and his sons stayed together in one camp with some of the possessions and wives, while the rest of the property and wives were in another camp.9 He assumes that Yaakov trusted in Hashem's promise10 that he and his children would stay safe and so he felt no need to split them.11
"וְהָיָה הַמַּחֲנֶה הַנִּשְׁאָר לִפְלֵיטָה" – Purpose of the division – Yaakov hoped that if one camp was attacked, the other would be able to escape. The word "פְלֵיטָה" is understood as "refuge".
Why send to Seir? According to both these sources, Esav had not yet permanently moved to Seir, but rather lived there part time. As such, it was a very real possibility that Esav might come to attack Yaakov upon his return leading Yaakov to send messengers to test out Esav's feelings towards him.12
Esav's intentions – Both these sources assume that Esav's entourage was intent on battling with Yaakov.
"וְהִכַּנִי אֵם עַל בָּנִים" – According to R. Avraham b. HaRambam, these words reflect Yaakov's fear that Esav would have no mercy and attempt to kill not just him but his entire family. The Netziv, in contrast, understands that Yaakov was concerned that Esav might kill the mothers as they protected their children,13 but not that the children themselves would perish.14
Unanswered prayers – Neither of these sources addresses the issue explicitly, but according to R. Avraham b. HaRambam, it is possible that Yaakov's "being left alone" was an attempt to attain prophecy in solitude,15 and the ensuing vision16 of the struggle with the angel/man was Hashem's answer to his prayer.17
The struggle with the "איש" – Both R. Avraham b. HaRambam and the Netziv assert that the "איש" came to bolster Yaakov's confidence that he would be able to defeat Esav.18
Rearrangement of wives and children – After being encouraged by the struggle with the angel/man, Yaakov no longer felt it necessary to split his camp, but he did rearrange his family.
According to R. Avraham b. HaRambam, the assembly line was a show of honor; he lined the family up according to their importance much the way dignitaries might be ordered in front of a king.
Netziv, in contrast, suggests that this was a sign of submission. Furthermore, since Yaakov had been hurt in the thigh by the angel, he was concerned that this might mean that Esav could still harm him a little, even if he would not be victorious. As such, he placed those less dear to him first that they should absorb whatever blow might be hit.
No Longer Possible
Though Yaakov wanted to split his camp right up to the moment of meeting, the struggle with the angel/man prevented him from being able to do so.
"וַיַּחַץ אֶת הָעָם אֲשֶׁר אִתּוֹ" – Who was to be in each camp? According to this approach Yaakov put his servants and hired hands in one camp and his wives and children in another.
"וְהָיָה הַמַּחֲנֶה הַנִּשְׁאָר לִפְלֵיטָה" – Purpose of the division – The first camp was to act as a decoy and stay put to detain Esav, thereby affording Yaakov's immediate family an opportunity to escape from danger.20
Esav's intentions – According to Rashbam, Esav had no evil intent and the 400 men accompanying him were an honor guard coming out of respect to Yaakov, rather than an army planning to attack. Yaakov, though, did not trust his messenger's report and feared that Esav must mean harm.
"וְהִכַּנִי אֵם עַל בָּנִים" – These words highlight that Yaakov's main concern was that Esav would take out his vengeance on Yaakov's immediate family (the mothers and sons) specifically. It is for this reason that it is they whom he attempts to bring to safety.
Unanswered prayers – According to this approach, Hashem might not have immediately reassured Yaakov because Yaakov had misinterpreted Esav's intentions and he was really in no harm. Moreover, according to Rashbam, Yaakov's whole plan to flee was misguided and he was punished for his lack of trust in Hashem. Hashem relayed this message to him through the confrontation with the angel/man (see below).
"וְהִנֵּה גַם הוּא אַחֲרֵינוּ" – Rashbam asserts that when Yaakov sends the gift to Esav and has his servants say that Yaakov is following shortly, this a ruse intended to deceive Esav while he in fact ran away.
Crossing the Yabok – Yaakov's original plan was to have his personal camp flee to safety across the river, leaving the other to waylay Esav.21
The struggle with the "איש" – According to Rashbam, the confrontation was both punitive (for his lack of belief in Hashem's providence)22 and preventative. The angel detained Yaakov overnight, preventing his flight and forcing him into a meeting with Esav.
Rearrangement of wives and family – Perhaps, when Yaakov realized that he no longer had the opportunity to split his camp and have his family run to safety, he tried to at least order his loved ones so that the most precious would be furthest from danger.