Short answers, pulled from the story.
The Japanese word tera derives from the Aramaic word dērā or dairā meaning Monastery rather than from the Indian word vihara. This linguistic path suggests transmission by first Central Asian translators of Buddhist scriptures such as An Shigao or Lokaksema.
Shintoism first encountered Buddhism in the 6th century when shrines adopted permanent structures and architectural concepts from Buddhist temples. The syncretism known as shinbutsu shūgō led to mixed complexes where shrines were accompanied by temples until Meiji era laws separated them.
Four main styles developed including Wayō Daibutsuyō Zenshūyō and Setchūyō. Wayō style emerged during the Heian period while Daibutsuyō appeared in the late 12th or early 13th century introduced by priest Chōgen based on Song dynasty architecture.
A 13th-century text describes shichidō garan as a temple containing seven elements: kon-dō tō kō-dō shōrō jiki-dō sōbō and kyōzō. These seven listed elements form standard spatial organization found in many complexes though what counts varies between temples and schools.
Enryaku-ji sits atop Mount Hiei north-east Kyoto said defend city evil spirits placed that direction. Arrangements mountains geographic features particular directions play important roles continuing long custom with Eight centuries after founding Tokugawa shogunate established Kan'ei-ji similar direction protection Edo Castle.