The debate about whether D&D does Sword & Sorcery well is an ongoing one. Personally, I'm on the side that says it doesn't.
More importantly for this question, I would not go with a class-based game for a 1-2 person party. That situation pretty much requires that PCs be generalists, or else be punished for not having a well-rounded party. Also, with a smaller party, I find that you tend to do more RP and skill checks, and less straightforward combat. So I'd want a rules-lite game with a decently rounded skill system. I wouldn't want something too granular, though. You don't want your players to be stuck because neither of them have any points in basket-weaving or whatever. Basically you want a game where any character can do most activities and at least not be hopeless at it.
Mythras might do the job, but it's a little chunkier than I'd go for. I'm in a 2d20 Conan game right now, and it's honestly just not a good system. Barbarians of Lemuria would be my pick of the ones you mentioned. Since it's just attribute based, I think it'd probably result in the fewest occasions where your players can't do something just because they didn't bring the right character type.
I'll throw in an outside suggestion for Savage Worlds Lankhmar. I have the book, and it's pretty well set up for making S&S heroes. There's an unofficial Conan setting for SWADE, too, if you can get a hold of it. If you want something on the more fantastical side, "Atlantis: The Second Age" for Omni System (so the same rules as Talislanta) might serve as well.