Well, yes and no. It depends on the context f(^_^;
Since Japanese doesn't have articles like "a" and "the" or plural nouns like we do in English, レストラン can be translated to "restaurant", "restaurants", "a restaurant", "the restaurant", or "the restaurants" (I think I got them all.) If 一 (いち) is inserted into a sentence to modify レストラン, then it can limit the possible translations to just the singular ones. You'd have to use context to narrow it down further than that.
I'd really suggest adding "です。" to the end of singular word questions like this to form a more complete sentence. Also helps build the habit of knowing how to use forms of the copula.
In another app I use where the speech is slower, it sounds like re ss to ran. I used double consonants to emphasize that all the syllables take about the same amount of time to say.
First and probably last! This really isn't the trickiest question in this lesson so I doubt there will be many questions unless they're about katakana or culture, so I declare myself king of this question!
The pronunciation is very quick, do they say "suto" or just "sto" in this word?
I beleive the pronounciation is ‹ resturan ›. I agree that it should be a bit slower but Japanese people speak quite quickly so I gurss its a way of becoming used to the pacing.