Yes, you can say "The vibe was good there," and it sounds natural. "Vibe" is a more casual and modern way to describe the atmosphere or feeling of a place. So, both "The atmosphere was good there" and "The vibe was good there" are correct, but the latter is more informal.

Your sentences are perfectly understandable and grammatically correct. Most native speakers (at least in the US) would drop the word "there", used as an unnecessary pronoun in this case. Since we know you are talking about the beach you would simply say "The atmosphere was good/It had good atmosphere" or "The vibe was good / There was a good vibe".

It does not sound unnatural. "Atmosphere" and "vibe" are similar enough that a native speaker will understand what you mean given the context. It is worth noting that "vibe" is becoming more common in modern English, at least in the United States.