About their involvement with the objects, maybe there are only certain dimensions that are aware of them? They could be objects that have the ability to transport/warp matter to different dimensions(among other things). I was thinking that maybe there is one particular dimension with a gate where the 4 objects need to go, once all 4 of them are there they open the door to the fountain of youth(or something?). The main bad guy at this point Shiana, is trying to gain access to the fountain of youth so she's attempting to gather all of the objects herself, using one that she stole from the Order to travel around through different dimensions.

The objects themselves choose specific people. They find them when they need too and even if they loose it the item will come back to them somehow(think Berserk and the Behelits). I'm not sure if they've been chosen for a specific task or anything(we can always think things out later), but the only ones who can make use of them are the people who are in possession of them.
If the current holder of an object dies, it automatically chooses someone new. But they could be from a completely different dimension than the one that the current holder was from, or died in.

I guess we could always so something with NE,NW,SE,SW, directions too if we get more people to join? Or we could implement it now? what do you guys think?
Keep in mind that all of this info isn't exactly official and can change at the drop of a hat, this was just an initial idea of mine.