@idonotlikeusernames I’ll try my best 
Obviously, none of this is legal advice, disclaimer, disclaimer, it only applies to US law, disclaimer, disclaimer, this is purely for informational/entertainment purposes and not for the purpose of providing legal advice, disclaimer, disclaimer.
As to contemporary movie quotes, there’s two ways they could be protected: under copyright law or trademark law.
Copyright law probably wouldn’t be much of an issue, since you can’t copyright a word or phrase, those would get trademark protection instead. Additionally, if you only use one quote from a movie in the course of your entire game, that would most likely be considered de minimis use (which isn’t the same thing as fair use), and therefore not a copyright violation.
Then there’s trademark law. A movie quote is also unlikely to get trademark protection because a trademark is used to identify the source of a product. There are relatively few quotes out there that people would immediately identify with a movie, and of those, even fewer that haven’t entered the cultural lexicon to the point of becoming generic, and therefore losing trademark protection. And to sustain a cause of action for trademark infringement in the first place, they would need to show that your use of the mark (the quote in this case) would cause confusion in the minds of consumers as to the source of the product, which seems pretty unlikely.
This is a pretty good article on the subject, if you want more detail: http://www.ipbrief.net/wp-content/uploads/2013/06/Shaw-Article.pdf.
As for characters and their names, copyright would protect who the character is (so you can’t write a choice game about Gandalf, the character from Lord of the Rings); trademark would protect the name. If the name was trademarked (and you can search the USPTO site for US trademarks), then it comes back to “is it going to cause confusion to consumers.” If your Gandalf is a cigar smoking garbageman, probably not. Then there’s the issue of trademark dilution. For example, George Lucas sued one of the members of 2 Live Crew for calling himself “Luke Skyywalker.” The judge issued a preliminary injunction prohibiting him from using any variation of the name “Luke Skywalker” 2 Live Crew’s use of sexually explicit lyrics could “dilute the distinctive quality” of the Lucas trademark. So if you do have a Gandalf, don’t have him do anything inappropriate 