Re: person names, you should know that having a family name is a fairly recent custom for most peoples of the world -- there are some exceptions, such as Chinese people that have used family names for a very long time, and Romans also used them. But before modern times it has been far more common to use patronymics (that is refering to someone as the 'son of X' or 'daughter of X') or bynames (often based on professions, such as 'X the barber' or 'X the miller') as the means to identify a person apart from those who bear the same name. So when family names started to be used (possibly due to a law that made it mandatory), a family either would have to decide on what to call themselves, or the community they live in would decide a name to call them by. Out of convenience, they might decide to base it on a byname. Eg. the family of Burt the Baker would adopt Baker as their family name, thus being called Bakers from there on, and their descendants would inherit that name regardless of whether they actually continue to practice the profession of baking.

Re: extra question, a place name for a geographic feature such as a river or a mountain may or may not feature the descriptive word as part of it. Your example of Cilen Antar might be kept in it's full form, or it might be shortened to just Antar, depending on what antar means and whether it's actually a meaningful word in the language of those who use it. For example if antar was to mean, say "green", then Cilen Antar would be "green hills", and it could feel silly for the people to refer those particular hills as Antar because they'd literally just be saying "green". But if the meaning of the word antar were to be forgotten or otherwise unknown (being originally from a different language, for example) then it wouldn't feel unnatural for the people to refer to the hills simply as Antar.

This is not a hard and fast rule though. Consider, for example, the Rocky Mountains - they can be called "the Rockies" without it being confusing or sounding silly, even though it's just a plain word in english.