Lu Xun, Guan Yu, Ma Liang, Zhuge Liang, and Zhao Yun's biographies in Chen Shou's Sanguo zhi (Chronicle of the Three Kingdoms) make no mention of Liu Bei's motivations, but Liu Bei's biography states:

"At the start of the sixth month, the First Sovereign was angry with Sun Quan executing Guan Yu, so he proposed an Eastern expedition. Seventh month in Autumn, he led troops to attack Wu. Sun Quan sent a letter to the First Sovereign to ask for peace. The First Sovereign was angry and did not accept."Chen Shou, Sanguo Zhi, Liu Bei's biography.

Sun Quan's biography also has: "In the twenty-fourth year of Rebuilt Tranquility (AD 219), Sun Quan approved of Lu Meng’s plan to capture Jing Zhou and in the process had Guan Yu and his son, Guan Ping, killed (1). For this Cao Mengde bestowed the title of Lord of Nanchang.

A year later, Cao Pi succeeded Cao Cao as ruler of Wei and declared himself Emperor. In an act of revenge, Liu Bei led his army against Wu in that same year, threatening Wu’s position."Chen Shou, Sanguo Zhi, Sun Quan's biography.

Although there was no historical Peach Garden Oath or formal brotherhood established among Liu Bei, Guan Yu, and Zhang Fei, they'd been fighting together for thirty years, and Chen Shou states they slept on the same bed together. Wu betrayed the shaky Shu-Wu alliance and seized Jingzhou. Attacking Wu would get Jing back and avenge Guan Yu at the same time (had it succeeded.) Sanguo yanyi has Liu Bei telling Sun Quan to "wash his neck, for the executioner's blade is coming," but there seems to be no record of him attempting to take over all of Wu and execute Sun Quan outside Luo Guanzhong's imagination.

I can't find anything on Liu Bei's advisors trying to dissuade him from the expedition. Kongming.net's History section has translated Sanguo Zhi biographies for most of the big names from the novel and is a good resource.