So, let’s do it. 
Maybe we should adapt the characters first - who it who in an SW? Also we could search SW actors fro them.
Oh - Eli Wallach as Thénardier. The role screams for him. Rat, coward, evil, sometimes funny, robs dead people and survives everything. 
So I’d say Thénardier is a Mexican cutthroat who has very small reward on his head, being unworthy.
Ok, I’ll bite. This may(or may not) be an unpopular choice for Valjean but, being the unapologetic fan of Terence Hill that I am, I vote for my man. More so based on his character in March or Die, not necessarily any spaghetti anti-hero he has portrayed. Not to say Trinity or Nobody couldn’t handle Jean Valjean. ;D
I adore Terence Hill. But… is he strong enough to lift a runaway cart?
I am thinking about making Valjean Mexican or gringo. If Mexican, I’d say Volonté. He could do anything. If gringo, maybe Franco Nero. But Hill could do it, I think. 
Or… how about Trintignant?
How about Peter Lee Lawrence for Enjolras? He’s blonde, nice and can be tough. And this would make Enjy the Gringo Who Is Fond Of Revolutions. And we could make Tomas Milian Grantaire, who is fond of any form of alcohol, and a fan of Enjolras.
How about the ladies? Linda Veras (Banjo’s girlfriend) could be a pretty Fantine.
Nobody? :’(
What do you say to William Berger?
I mean, he wears black, is tall, has cold eyes, and is attractive with sideburns. 
He’d do a great Javert.
William Berger is the ideal choice for Javert
It’s a good idea to give Valjean a Mexican background since he has to join revolutionary forces in the second half of the story
A man of mixed blood would be ideal, American father, Mexican mother, who gradually becomes aware of his solidarity with the Mexican ordinary people
I’m not sure about Terence Hill, nor of Volonté, maybe Franco Nero would be a better choice
I can’t imagine Linda Veras as Fantine, don’t know why, beautiful woman, but not really corresponding with the mental picture I have of the character
I’ll have to think about another name