Shige/Kiku had no connection to the subconscious until reaching the 8th cycle — they were essentially nonexistent as themselves as long as the reincarnate was alive, only getting to "exist" between each cycle, before another reincarnate took hold- (2/?)

The 8th cycle was given a special connection that didn't exist before that, one that bridges the unconscious to the subconscious It gives Shige/Kiku chances to communicate with their living counterparts (even if they don't realize who they're talking to at that point) (3/?)