For the most part, I do believe that Emerson and Thoreau would see much in way of Transcendental ideas in the film. The basic idea of Mr. Keating being a force in both his own beliefs and in his teaching methods are Transcendentalist. They stress the idea of embracing one's own identity and not following. When Emerson speaks of these ideas, he is stressing the same elements that Keating is. Mr. Keating teaches on the level of self- awareness and breaks from seeing instruction as purely and solely content based. When he instructs the students to "tear out" the introduction to their poetry texts, I think that Thoreau would appreciate Mr. Keating's stance of civil disobedience, refusing to follow that which he knows in his heart is wrong. These are Transcendentalist ideas.
In terms of the students, the Transcendentalist understanding is also evident. Emerson and Thoreau would laud the students for seeking to find their own path. Certainly, the crushing force of social conformity that results in Neil's death would prove the fundamental challenge for Emerson and Thoreau to demand change to such a state of being, helping to push the advocacy for Transcendentalism. The ending, in which Todd and the other students demonstrate civil disobedience in support of Mr. Keating, would be an example of Transcendentalist ideas of embracing one's own voice and giving flight to it.
If there would be an area of disagreement, Thoreau might have a problem with Keating telling his students to "be wise, not stupid" in their embrace of individuality and challenging the system. I think that this might be an area where Thoreau would claim that any demand for change in such a regimented setting- foolish or not- would be a good thing. Another area would be a minor point, but I think that it would be worth mentioning. Keating stresses, as does the film, the idea that community and a sense of togetherness is how being should be constructed. The individual is only as good as when they are part of a group. I think that Emerson would be fine with this, but Thoreau might have a slight problem with this. Thoreau defines his own embrace of Transcendentalism as an individual process, one that is driven by the sense of solitude and being apart from others that allows a sense of connection with all aspects of being to be present. Thoreau is more inclined to sacrifice being with other people and even negotiating on community in order to be more in line with his own sense of self. I think that this is where he might have a slight challenge with the communitarian premise put forth in the film. Yet, I do believe that Emerson and Thoreau would be able to give their support to the ideas of Transcendentalism being reflected in the film.