Francisco: sounds like a great trip. I'm not sure if I'd get either bike for a trip like that. In theory, disc brakes are the better choice but cantis but discs may not be as easy to service. I'd get something a bit overbuilt that takes 26 inch wheels (tire availability is going to be an issue) and which has very forgiving gearing. I can't tell what kind of crank these bikes some with but I'd want a steel 24 or 22 tooth inner ring. I'd get bar ends rather than brifters (if you drop the bike and mess up the shifters you are out of luck but the bar ends should be fine). I'd also keep it as simple as possible in terms of parts.

Where are you located when it comes to buying bikes? How much are you willing to spend? If you are in North America, the Surly Long Haul Trucker is well regarded, comes in a 26 inch wheel version, and has a sensible parts selection. There are bikes out there designed for touring off road that would work well for you; I'd take a long look at the Salsa Vaya for that reason.