Question: Several people have mentioned that the film makes a point of showing how Belle is the only literate person in her village. If that's the case then how does the village bookseller manage to stay in business? He couldn't possibly afford his shop and the collection of books he has if Belle is his only customer.
Answer: There is no definite proof she is the only literate person in her town, but the people we do see are not as interested in books as Belle. There is no information as to how he keeps his book shop open, especially if he is willing to lend books to other people in the town.
It's not a "bookshop", it's a library. And it doesn't seem like he only lends books.
Answer: As KristenLouise3 said, there is nothing to indicate that only Belle is literate. Several men, at least, could probably read. The book seller could sell to them, sell at a market somewhere, and the village might have some amount of travelers who pass through.
Question: Why does everyone love Gaston? I can kinda see why from his looks/biceps but is there another reason why they love him so much?
Answer: I would say he was admired rather than loved and for very superficial reasons. He is young, handsome, manly, and extroverted. People often admire and wish for those traits. They project other non-existent qualities onto such a person while blind to their flaws. In Gaston's case, he is arrogant and self-absorbed. It is very typical of our society to celebrate people for their physical attributes, even though they may lack integrity in other areas of their lives.
I'd have to disagree. The film takes place in the 1790s to early 1800s if you ignore the Eiffel tower in Be Our Guest. So not long after the revolution at all. The peasantry was suffering quite a bit of food insecurity, which we see reflected in the opening song, (the eggs are too expensive, the bread is stale, etc.) Gaston is a hunter, and he's able to provide for his village which might otherwise have suffered a bit. I'd argue that his super-inflated ego may be a result of the praise he rightly earned.
Answer: I get the impression that Gaston comes from a family with some amount of wealth and social status - maybe not royalty, but perhaps more wealth and status than most people in the town have. Also, despite being vain and arrogant, he is bold and somewhat cunning. Many people like to latch on to a "leader" type.
Answer: The Beast is self-absorbed, selfish and cannot see the good or innocence of people (hence why he was changed into a beast). He assumed that the only reason Maurice would be there is to stare at "The Beast" (after all... EVERYONE must know about "The Beast" in the Beast's mind).