Yes, there is a menage a trois in the DYS flashback, but not a love triangle. The two are different. The latter almost always entails jealousy, the former does not necessarily . . . .The point is, Leone gives no indication that there is anything dark going on between Sean and Sean prior to Nolan's capture by the British. Also, there is absolutely no reason to suppose that Mallory betrayed Nolan before Nolan betrayed the cause. Without any such evidence, it is best, IMHO, to stick with the simplest explanation the film affords us, namely: Nolan and Malory shared a political cause and a woman (who may symbolically represent that cause); Nolan fell into the hands of the British (perhaps in some mundane way); Nolan, under torture, betrayed his fellows; Mallory took revenge on Nolan (with Nolan's consent) and immediately regretted it; years later in Mexico he found a way to atone for his deed, and at the point of dying, experienced something resembling a state of grace (represented by the idyllic flashback that reunites Mallory with his friends in the Edenic Irish countryside). Other, more convoluted readings of the story are not supported by the film.
As far as I know, the major editing of Leone movies as in OUATITW, DYS and OUATIA was done by the studios and not by Leone himself.
That's pretty unlikely.As far as I know the last flashback wasn't in any released version. It was restored in the mid 90s in Italy.
I beg to differ, and I don't know how old you are, but I remember seeing the full version on its initial release in 1971 in a theatre in Montréal.
I have to believe that Leone wanted that full final flashback in the film. Without the final flashback, what do the flashbacks accomplish? It shows us that Coburn once betrayed a friend, that's all. The girl is useless without that final flashback,
I always thought that Nolan nods towards Coburn, giving by that his approval to kill him for the treason.