For the scene in the forest with the ascetics where Siddartha becomes emaciated from lack of food, Keanu Reeves went on a crash diet of oranges and water.
Early in the movie, when Kenpo and the 3 other Tibetan monks are driving north on the top level of WA-99 the movie cuts to a separate shot of the same group now traveling north on Interstate-5 and then again south on the lower level of the WA-99 viaduct. However, as the scene continues, the group ends up atop the Queen Anne neighborhood, which is a northern part of Seattle.
Champa: [as they observe Lama Norbu, who is old and ailing, in a state of deep meditation]
Someone like Lama Norbu can remain like this for ten days. Or even more. He can sit like a mountain, serene and unmovable. And he can meditate deep and vast as ocean. And then smoothly, while doing meditation, he can enter into the state of death, with his own will.