Probably Toyota, these are everywhere so parts are available everywhere as well as tires, wheels etc. Also fuel quality varies and going around the world, you need something that runs with almost anything that burns. That with B series engine would be nice choice, or wagon variant, you could have air mattress at back for sleeping, so no need to have a trouble with a camper. All mighty 85-98 hp from NA 3 - 3.4l diesel engine. There is no point going around the world trough highways, experience is at smaller roads
Probably a 2018 BMW M550d xDrive Touring, with a roof rack, and it's beastly quad turbo diesel engine.
The 2018 Toyota 4Runner TRD Pro. This is one of my favorite vehicles. It gets decent gas mileage, and it has a locking differential along with a smart 4 wheel drive system. I think this is one of the best vehicles to do something like this. (I want one just like this!)
Unless it's a plug-in hybrid, or something like a Tesla. They would have to build multiple stations for those who happen to own those vehicles (unless they have their own refueling equipment). ...or just go use a airplane, if you really don't want to spend multiple weeks getting from one destination to another.
Probably this. If I was to circle the Earth, and I was limited to one car, I'd want something that could overcome the kind of obstacles that could potentially stop me. This Anglia can fly, so I could just kick it into flying gear and fly over whatever's in the way, and later return it to the ground afterwards.
Contemporary electric car is the worst car type to travel around the world with. Most countries lack developed charger networks or lack charger stations at all. Even when traveling through countries where charger networks are present, you'd have to travel at much lower speeds than comparable ICE cars just to get to the next charging station. And then wait for your car to charge.
...leading to more construction of more hotels/motels, which grabs more money from each country, and also grabs more people to help construction of hotels/motels. It sounds okay (though I wouldn't think that) at first, but knowing that some countries don't have a good enough economy to handle country-wide construction of lodging establishments for civilians, it becomes way too far-fetched. Add very severe traffic (especially with cities that already have heavy traffic) to that, and also overworked employees... you got yourself a heaven of disaster after disaster.
I like how nobody listed cars outside of Europe and Asia yet..... EDIT: Except for one, nobody else listed non-European/Asian vehicles.