I absolutely love the thought behind your bracelet. i recently bought a pandora essence bracelet with smoky topaz/compassion to represent my pup that recently passed.
as for wearing your bracelets, it depends. i sleep, shower with my bracelets, i feel pandora is good quality and that it is ok, but since you have the charm key to my heart on there, i would be a bit concerned about the key falling off in case you were to do something to your bracelet in your sleep. However, with practice, it becomes easier and easier to open and close the clasp, so i would take it off for sleep because of that one particular charm. Hope that helps!