Exactly -  the same argument applies there.   mp3 is designed for small file sizes for internet streaming and so on, but brings with it a lot of compression artifacts that can cause trouble if you try to export the file again.

.wav or .aiff at maximum quality are my usual choice.

Aside from FX shots which often involve frames, I use image sequences as my final output format - at least for projects that I think will have any shelf life at all.    A directory of individual frames plus a soundtrack audio file makes the project more future-proof.   You don't have to worry about your master file becoming outdated because of the codec you used, etc.   

Whatever format I need my project to be in, I just load the original frames and output as needed.    I've lost count of how many times I've exported the Pink Five series to keep up with new codecs and formats, but all the versions have been generated from the same set of original master frames.

Nice!  Never seen it all laid out like that before...

A few others I can think of  -

At first Marty's sister is unpopular, then at the end is told by the brother "hey, I can't keep track of all your boyfriends" or some such.

The scene with Jennifer in the town square is completely crammed with setups - in addition to the clock tower flyer, there's also:

Marty sees the 4x4 truck, later he will own it.

Marty frets about sending his demo tape to record companies, and Jennifer says "Like Doc says, if you put your mind to it, you can accomplish anything".  Marty answers with "what if they say I'm no good?...  Jesus, I'm starting to sound like my old man",    Later George says the same thing almost verbatim about his writing to Marty, and Marty gives him the "put your mind to it" line.   Which George then echoes again at the end, talking about his novel - "It's like I always say, if you put your mind to it..."

And the demo tape itself is a setup - (I believe) it's the same tape he later uses to melt George's brain.   (I admit I could be wrong on this one).

EDIT - oh, you had the 4x4 in there already, I missed it.   Carry on.