Question: What is the principal's problem? Why is he taking it out on a 17 year old?
Question: Given that the entire McFly family's circumstances have changed at the end of the movie due to Marty altering the past, shouldn't Marty's whole life have gone down a completely different path from childhood on? What are the odds that he even still knows Doc and Jennifer in the revised 1985 (let alone has the exact same date planned with Jennifer for the very same evening), given that everything else has changed?
Answer: The suggestion is given that he was the only "normal" person in the family and when he changed the past his parents and siblings became more "normal" people as well whilst he stayed as he was, despitegrowingup with different parents and siblings, since he was "normal" anyway. This totally ignores the linear timeline idea given during the entire movie, but it's obvious that was the idea.
You're absolutely right about Marty being the only "normal" one in the family, but that doesn't ignore the linear timeline idea. There are two different Marty McFly's by the end of this movie. There's the one we follow, who grew up with unhappy parents, and then there's the other Marty McFly who grew up with cool parents. We see the 2nd Marty go back to 1955 when Marty gets back to the Twin Pines mall. The idea isn't to ignore the linear timeline idea, but rather to imply that unhappy parents or not Marty will still always be Marty.
Except for the fact Marty kept being in danger of disappearing if his parents wouldn't get together. If his old self would disappear from his parents not getting together then so he should if his entire life is different and he would be a different Marty just like his siblings. Even if it's only memories rather than an entire personality.
Answer: It's definitely a paradox. Marty actually goes back to the life of 2nd Marty, but if that's the case then original Marty should have still faded away since he created a new timeline when he gave George confidence. Original Marty shouldn't exist anymore at all, he should have faded completely away on the stage. I've said it before and I'll say it again: time travel movies are a mess.
The new Marty isn't a different person entirely; he's just the same guy who was raised in a slightly different environment to the original timeline. Marty's actions in 1955 have ensured that his parents will have three children, and he will be one of them. His existence is completely secured in the timeline.
Question: Are we ever given any suggestion as to what offence Lorraine's brother was incarcerated for?
Answer: Not in any official, canon source. In the Back to the Future comic books published by IDW he is an aspiring member of Biff's gang and gets arrested breaking into the home of Doc Brown's mother in an attempt to steal a large sum of money. It must be reiterated that the comics are non-canon and this should be taken with a grain of salt.
The comic books are so skewed from the movie events, they cannot be considered canon. "Jailbird Joey" was only a baby in a playpen when Biff and his gang were seniors in highschool. Unless Biff and his highschool buddies were still recruiting gang members into their mid-30s, there is no way Jailbird Joey would be trying to join their gang.
While the answer does state the comics aren't cannon, it's the only place that really delves into Uncle Joey's criminal history since the film's didn't need to spend time discussing the exact nature of his crimes. However, it would not be unreasonable (or even unheard of) for Biff to be recruiting members for his "gang" at 35. Plus, Joey wanting to be part of Biff's gang wouldn't necessarily require Biff or his high school buddies to be personally involved in recruiting young Joey.
Question: During one scene in 1955, Marty mentions John F. Kennedy, and nobody has any idea who he's talking about. Would Kennedy really have been a totally unfamiliar name to most Americans in 1955? True, he wasn't President yet, but he was a popular Democratic senator from a prominent family.
Answer: He was both a war hero and a senator, but unless Lorraine's father followed politics closely he might not have recognized the name, especially since Kennedy wasn't a senator for their state.
Plus it would be unheard of to name a street after a living politician from across the country.
Answer: Keep in mind, there was no TV news in that house (they just got a TV). And I don't see the dad being one to read any further than the sports page, or listen to anything but comedy on the radio.
Question: At the dinner table in 1955, Marty's grandfather is there. It has always appeared to me that there is something off about his appearance. He seems to appear as if he was not actually there, and that he was spliced into the footage from another movie. The lighting on his face, his style of hair, the quality so to speak of him, just seems off from everyone else. He almost seems like he is from a black and white movie, spliced in and colorized a bit Is it supposed to be that he was to look this way, or did they actually take this actor's scene from another movie and splice it in?
Answer: I just pulled up this scene on YouTube, and I think it is just the lighting. The shadow from his wife's head is casting onto his right shoulder in a realistic way, which suggests the actor was there for filming. It would also be impractical logistically and economically to insert him after the fact, because they could simply hire another actor for the part if he was unavailable.
Question: At the end of the film when Marty sees Doc get shot at the mall the second time why is he crying when he runs over to check Doc? Couldn't he have just grabbed the plutonium that was sitting next to Doc's van, run back to the Delorean with it and travelled back much earlier to warn Doc?
Answer: Technically he could have done so, but that doesn't make it any less distressing to see his friend murdered.
Next to that he doesn't know how the DeLorean works, he doesn't know how to put the plutonium in (or doesn't want to risk using it wrongly, having only seen it loaded once) and he and Doc from 1955 have tampered with it to have it be powered by lightning so it probably wouldn't work properly anyway.
Question: Right when Marty gets back to Doc before he goes back to 1985, he's praising his dad's actions of the night. One line that's bothered me ever since I can remember is "My dad laid out Biff. He's never stood up to Biff in his life." And then the Doc pauses for a second and gets a strange look on his face and says, "Never?" To that, Marty says, "No, why?" and the Doc shrugs it off saying, "Nevermind." What's Doc thinking? The best I can come up with is that he's wondering what effects it'll have on the future, but that's a rough guess. If anyone out there knows, I'd be happy to hear it.
Chosen answer: I think that is *exactly* what he is thinking. He realizes that by standing up to Biff, George may have irrevocably changed his personal future, and therefore affected Marty's future as well. This is exactly the sort of thing Doc was so eager to prevent by refusing to hear any information about the future.
Answer: The original film was not written with sequels in mind. The sequels were only created after the overwhelming box office success and popularity of the first film. The ending is a "joke" because of how much more absurd the story has become, and the fact the audience doesn't actually see the future. Of course the joke is ruined somewhat because sequels were eventually produced and we did actually see the future, Marty and Jennifer as older adults, and their kids. When viewed in the context of a stand-alone film (and in the four years audiences had to wait until the sequel was released) this ending was indeed quite funny at the time.
BaconIsMyBFF