The owner is confusing Rosslorean with the Dark and Dense Woods, the former being the Golden Grove, which is the dominion of the Lady Gaillardriel, and the latter being the home of Legolas, which does not appear in the movie
Why are there two Elven kingdoms, which I'm afraid I have to ask the opposite question, why can't there be two elven kingdoms? Humans, and dwarves don't have just one country, so why do elves have to have only one unified country?
Rivendell and Ross Lorian are very close, and the wife of Elrond, the leader of the elves of Rivendell, is Calebrian, the daughter of Lady Galadriel