It is, I believe, a checkpoint-based system during actual missions (which can be quite lengthy), but I'm not sure whether you lose items in these instances.
When you're just free-roaming, taking outposts and causing mischief, when you 'die' you get revived at the nearest friendly outpost, but lose some of the salvage you picked up.
Yes, it's true. The VR version will be available through Oculus Home, but if you get the non-VR Steam version you'll also get a free key for the VR/Oculus Home version.
But not gonna buy Oculus so there's that :(