I couldn't ask if there was any credence to the possibility of a blood relationship between Ethan and "Scar" or if Ethan might have been part Indian. As for my own further thoughts on Ethan Edwards/Native American question, I think my conclusion can only be that there is no evidence to support it. A friend who read the book told me that is absolutely not in the original story and that Ethan's hatred for Scar and the whole Indian race is based purely on hatred for the "other"---not on anything more complicated. And it seems that everyone around him, his family and neighbors, would know if there were any blood tie because they knew his mother so well. How he came to know so much about their ways is a mystery, maybe based on nothing more than his loner experiences in Indian territory. What is even more intriguing is the mental relationship between him and these people: when he goes after "Scar" he almost seems to transform into "Scar" alter-ego. He tracks and pursues like one of their own. And when he shoots out the eyes of the dead Commanche, dooming its "spirit to wander between the winds alone, forever"---he is in fact dooming himself to exactly this same fate. The last scene of the film shows him wandering off alone into the wind-swept landscape.
One interesting point Stoehr hilighted and which I have always felt myself about Ford's films in general, is how he used comedy to break the tension. Stoehr quoted from other critical analyses to support his belief that Ford used humor, transitioning from drama immediately into a comic scene, the way Shakespeare did. Because both artists understood that is what life is like. He further quoted another critic, a French one I beleive, who said that if The Searchers had maintained a completely solemn tone throughout (as many still wish) it would have been "a less sublime film". That's how I feel, too.
So, that is basically what I got from this last viewing.
I have to mention that the audience this time was even more enthusiastic---they clapped at JW's name on the screen and what's even more surprising, they clapped at John Ford's name!
I sat next to an old guy who had seen The Searchers when it was released---and he paid only 25 cents. He was really knowledgable about old movies in general, though he was simply a fan and no critic or historian at all. In fact, he was so enthusiastic he would sing along with Stan Jones and talk to the screen and generally drive some of the intolerant spectators around him crazy. I enjoyed his enjoyment, though. 
