Interestingly, when I first started the Future Arc I interpreted Byakuran's ability not as communicating between different versions of himself but that he simultaneously existed as the same person in all time lines. It's how I rationalized what happened with Ghost. In conjunction to it being difficult to bring someone from a different timeline into a different one, I thought it was impossible for the same person to coexist with themselves in the same timeline. So when Byakuran tried to bring Ghost, who at the time was himself, into our Byakuran's timeline, he was trying to break that rule. To have multiple of himself coexisting which resulted in one being forced to change: the intruder. That's why Ghost could continue as Ghost alongside Byakuran because they were no longer a singular entity but rather two separate beings.
