Yes to the last question. Actually since the universe is accelerating faster than light, every second more and more "things" get so far away they are "lost" to us permanently because light from them can never reach us anymore. At some point far far into the future, our cosmic horizon would be complete emptiness in every direction, and our galaxy would be the only thing that even exists to us anymore.

But to B and C, they don't exist for each other. Information from B can never reach C and vice versa.