Try: The guide told the tourists that there was a good seafood restaurant around the corner from the museum. You usually wouldn't use the word "it" in that context because it would be too ambiguous. What is "it"? The reader is not sure what you're referring to by saying "it". When you say specializing in seafood I assume you mean a seafood restaurant. Specializing in seafood also just feels awkward in that sentence. Lastly you would say "around the corner" instead of "round the corner". You'll find that many native English speakers may use the phrase "round the corner", but it is still grammatically incorrect.

Those two words tend be used synonymously. Though evidence tends to be used in a more formal setting like in a trial. Evidence is usually the proof for something, so with evidence you're proving that something is true. In terms of which one is stronger it all depends on the context that you'd be using it in. In that example evidence works better because it indicates that the narrator has tangible facts showing that man is not alone in the universe.