From what I’ve heard, that’s exactly what happened. The showrunner saw that some people on the internet predicted a major plot point, so they rewrote a bunch of it. Which is such a stupid thing for a writer to do. Who cares if some people predicted it as long as it’s still a good story?
Looking at military rank alone is insufficient. Soleimani was uniquely prominent and powerful in Iran, among the top people in the country. Pundits put him at most influential in foreign policy, less with domestic. He was a well-known public figure to boot (unlike any of the people you mentioned).