Yes. Because "time has no meaning there" there is always some version of "Soran" in the Nexus. Just like there is another Kirk and Picard.
It's the "echo" concept Guinan tries to explain to Picard.
.....or not. Because like you said, "who I know I guess!"
If we want to make sense of the bad writing, I don't think that's the echo concept at all. I believe that because Guinan and the others were yanked from the nexus when they weren't fully in there, that caused the echo. Guinan's echo said she couldn't leave not because it was impossible, but because there was a version of her in the time period that Picard wanted to take her.
That sure implies that if she exited at a point in history that she did not exist, that would be ok. She would just not be able to help Picard.
So what happens if she did exit at a point where she existed? The only thing I can think of is that if that happens, you replace the version of you that's outside completely. Why do I think that? Because there were not two Picards.
I don't think the echo is relevant at all.
What is interesting, and poor writing, is the question on this thread? Did the version of Soran that made it to the nexus stay there? It's not 100 percent certain, since we don't know if the nexus is immune from changes to the timeline. The answer is maybe, though I lean no, based on GR rules of time travel.
The time traveler can often be immune/protected from changes in the timeline. We have seen that. For example, when McCoy saved Edith Keeler, the rest of the crew, including McCoy, was not wiped out. So when Picard and Kirk beat Soran, Picard's failure to enter the nexus in the first place did not negate anything. Picard and Kirk were the time travelers, so that's that. But in this scenario, Soran was not the time traveler. He was not immune from changes, so by that logic, he didn't get in there.
The only certainty is that during the second timeline, there was a version of Kirk in the nexus that never exited, just as equal and original to the one that died.
That version never met Picard.
If the nexus is immune to changes in the timeline, then there would be two Kirks (one that met Picard and one that didn't), two Sorans (the echo from the 23rd century and the one that beat Picard's ass), and one Picard in there at all points in history.
