OUT WITH THE OLD.
This concept separates itself distinctly from the others in that it's the only one set in a different time period. This is, of course, essential to the plot working, but it also affords an entirely new set of perspectives from which to approach the morality of both the Western genre and the frontier landscape, as all of the characters will have views influenced by contemporary and even post-modern experiences.
By this merit, I've decided to alter the plot slightly so that I can adhere the story and the perspectives of the characters, good and bad, to more of an environmental message than an anti-nuclear energy one. While I think that both political/environmental messages have been explored more or less equally in the cinematic landscape, I also feel that the environmental message is more relevant currently, which helps to further establish the movie as a more modern look at the Western landscape rather than a dated one. With all that being said, it's worth bearing in mind that there's more or less no post-apocalyptic premise that doesn't have to wrestle with the consequences of nuclear fallout. Of course many movies don't touch on it, likely out of ignorance, but the fact is that after a few months of being unmonitored, which would be inevitable in an apocalypse, any nuclear power plant would overload and meltdown, causing a nuclear explosion and a huge radius of radioactive fallout. So, with that noted, I seem to have to retract my previous statement and embrace the fact that, whether civilisation collapsed as a result of an environmental or political disaster, there's really no way to explore a post-apocalyptic future without including a nuclear disaster theme. Still, though, there's no reason to limit the plot and message of the film to one of only the environmental or nuclear, when I can simply explore both, or have the nuclear aspect mentioned only in passing by the characters, who are more focused on and motivated by the fact that the world only 'ended' in the first place to due neglect of the environment by politicians.
An idea I've had is to use the beliefs and motivations of the characters to explore the consequences of the environmental and political aspects, but to feature a character who was born prior to the disaster, unlike the others, and is afflicted with the symptoms of radiation poisoning.
THE SURVIVORS.
'Gunslinger'.
The 'Gunslinger' exists not only as an example of the 'tough as nails' archetype, but also as a commentary on the Western male and female leads. Having no name other than an alias, and being infamous in the canon of the film as the lawless traveller of the wasteland is a chance to explore an entirely stereotypical iteration of the lead, and furthermore to explore how the morality and lifestyle of the outlaw translates to a landscape influenced by modern elements.
Eliza Wessen.
One of the settlers in Las Vegas, Eliza's purpose in the narrative is to establish the nature of the survivors, as she's to be written as a very kind, trusting character with heartfelt motivations. Although the audience shouldn't need the help, as the Deacon's intentions are clearly terrible, the presence of very likeable characters who would be among the casualties of the Deacon's plan helps add to the urgency of the protagonists defeating the Deacon.
Beyond all that, the twist - which is still to remain a secret in case I choose to move forward with this concept - provides Eliza with an opportunity for a very empathetic character arc, as she will be forced to confront her morality as she has a certain connection with the Deacon.
'Beans'.
My aforementioned irradiated character, 'Beans' is based on the 'Old Man' archetype of the Western. The Old Man almost always having some impairment that makes him a detriment is a great characters aspect for me to take advantage of in tailoring the Western to a post-apocalyptic future. Beans' impairment is his radiation sickness, which will progress as the plot moves forward until Beans' death in the final act of the film. Beans is also among the settlers in Vegas.
Jedediah Calhoun.
Jedediah is a preacher in Sheriff Hardwick's town, and is the only one of the townsfolk to openly accept Gunslinger's presence. Despite Eliza's kind nature and Beans' carefree attitude, Jedediah is the only person in the town who isn't under the influence of Hardwick's fear-mongering anti-outsider attitude.
Sheriff Clay Hardwick.
Hardwick was in the military before the disaster, and he was one of the very first settlers to establish a camp in the wasteland of Vegas after it struck. Now he oversees one of the settlement towns in the city and also serves as a messenger between his settlement and the others.
Hardwick and Gunslinger come into conflict with one another very easily, as Hardwick considers himself the law in the Vegas settlements. It's a fair statement; he was appointed by the townspeople, but Gunslinger disagrees with his authority.
The Deacon.
The Deacon holds a status more in the realm of myth than cultist. Nobody but his disciples have seen his face or know who he is. The Deacon pursues a return to society's past, hoping to assume governmental control and re-establish the world order from before the incident by eliminating any evidence of the new lawless wasteland, and anybody who refuses to follow him.
After some deliberation motivated by the necessity to reduce my pursued options down to only three concepts for the Specialist Study presentation, I've had to eliminate three of my six concept candidates.
I actually felt that the Once and Future West was one of my stronger ideas, and I'd have liked to pursue it further, but ultimately I think there are others I would rather explore further.