Short answers, pulled from the story.
The four major schools of Tibetan Buddhism are Nyingma (founded in the 8th century), Kagyu (11th century), Sakya (1073), and Gelug (1409). Each school is independent with its own monastic institutions and leaders, though they are closely related and maintain dialogue with one another.
The Nyingma school, the oldest tradition of Tibetan Buddhism, was founded by Padmasambhava (8th century CE) and Santaraksita (725-788), both of whom were invited to Tibet by King Trisong Detsen. Padmasambhava is revered by Tibetans as Guru Rinpoche, meaning "Precious Master."
The 14th Dalai Lama fled Tibet in 1959, following the Chinese annexation of Tibet after the Battle of Chamdo in 1950. He settled in India, where the Tibetan government in exile is based at Dharamsala.
The Rime movement, meaning "no sides", is a 19th-century nonsectarian movement within Tibetan Buddhism. Scholars Jamyang Khyentse Wangpo (1820-1892) and Jamgon Kongtrul (1813-1899) compiled near-extinct teachings from the Sakya, Kagyu, and Nyingma schools, producing scriptural compilations including the Rinchen Terdzod and the Sheja Dzo.
Deity yoga is a fundamental Vajrayana practice involving visualization of Buddhist deities, Buddhas, Bodhisattvas, and fierce deities, combined with mantra repetition. It proceeds through a generation stage, in which the practitioner visualizes a chosen deity and its mandala, and a completion stage, in which the visualization dissolves into the realization of ultimate reality.
Freda Bedi, a British woman, was the first Western woman to take ordination in Tibetan Buddhism, which occurred in 1966. Pema Chodron was the first American woman to be ordained as a Buddhist nun in the Tibetan Buddhist tradition.