I do feel compelled to counter Molly Dogs argument for a dual sport bike. He is a dirt bike rider who has traveled and recommends bikes by how they will perform on roads you will only occasionally encounter. You want more than one cylinder because you may be riding for hours at 120kph

I am a street bike rider who travels. Right now I'm in Chile, having ridden a totally inappropriate 1500cc cruiser here and deliberately and accidentally taking some roads that dual sports would have a tough time on all with a 16" front tire

Still, the best bikes for this trip are the compromise bikes, street bikes with some more ground clearance and suspension travel, V-Strom, Versys, F series BMW. These bikes though, lack an important component, they are not cheap.

What is cheap are road bikes of between 500 and 950cc. They can do any road, including the worst ones in Peru with a more aggressive front tire, such tires are available throughout Latin America.

Standards like Ninja 650, Bandit SV650 etc and cruisers like Honda Shadow and Kawasaki Vulcan are dirt cheap and bulletproof. Nothing like having a bike that you can afford to lose.

Shipping a bike from CA to SA costs about $325 and might be worth it to you.

"occasionally"? Are you sure? Have you ridden mountainous back roads in Colombia and Ecuador? Explored the thousands of miles of dirt roads in Peru's Northern interior? (Some of the best exploring in S. America.)
Lots more I could list.

I'm not just a dirt rider. I've logged around 500,000 street miles as well on over 50 bikes plus dozens of test bikes ... including Victories and H.D's.

Hey, you said it, not me! The above sort of tells it all!

Those bikes are fine but how do you know they're the "BEST". Have you owned and ridden any in Mex, C.A. or S. America? I have. They are not the best. The other component they lack is toughness and crash survival.

Cheap? Have you priced NEW or USED Dual Sport Bikes lately? The Honda XR650L, KLR650 and DR650 all go for around $5500 to $6000 new.

Used? MUCH cheaper. I paid $3500 for my virtually NEW DR650 Suzuki. By the way, I've OWNED and traveled extensively on ALL the above dual sports. All good but I prefer the DR650. Hundreds of used dual sport for sale everyday, usually in $2500 to $5000 range.

IMO, none of the bikes listed are ideal once off road, poor choice. And to me, sounds like the OP has intention to explore off road.

Really? Can you provide documentation on this claim? (I'd like to invest in this company providing this service ... and get in on the ground floor. )

Sure, for an ALL PAVEMENT ride some of the bikes you mention could work. But that does not appear to be reality here. As I mentioned in an earlier post here, travelers can take any bike: from a 100cc Postie to a 1500cc Victory.
Smart choices? Only experience can answer that one. But if you've got no experience ... then best stick to what you know.