Since you didn’t tell me how many units a “human” is I am going to assume that a human is 2 units tall. In other words, 1 unit is 1 meter.
Now come on, 2**32 meters (=4294967296) is 700 times the radius of our planet. And this is just one dimension of extent! Assuming your world has not much z-extent you have an area of 18446741531089 square kilometers!
Even if you have only one collision primitive or triangles per square kilometer you won’t find a server which has enough memory to hold all these objects, let alone CPU power.
No. I don’t know what would happen if you do so, but most likely nothing useful. One object should be part of only one world.
This is strange. I modified both my basic and my character sample in such a way that the objects are located around (17000, 0, 0), and I get no shaking at all. Can you post a working sample which reproduces your problem?