Look, if all you want is names for places and characters, there's no reason to make up a whole language. Most published fantasy writers have done nothing of the kind. It's too much trouble. The people who develop conlangs are usually interested in linguistics to begin with.
In my opinion, all you need is for the names used by each culture to have enough similarities so that they sound as if they come from the same (non-existent) language.
In your case you still have a problem. Still, why not get people to make up the names for you? It's much easier than constructing a whole language with grammar, vocab etc.
And yes, I am volunteering to help. I'm quite good at making up names.