Or worded differently: once i establish longer-lasting facts through narrative or 'create an advantage', are they aspects beyond the scene? If PC finds an item, for example, or some character aspect should change in the light of the narrative because it is no longer true. If something about the character is established in the narrative, should it be part of that characters aspects?
The short answer is yes. It is because of the Bronze Rule i.e. the Fate Fractal on Page 270 of the Fate Core rulebook.
The trick is to describe the elements you are dealing with in natural terms first. Look for logical subgroups or subelements. For example Super Porsche, a car with super tech, can be described as a character in its own right. In addition the Super Porsche's amazing engine can also be its own character.
Now you ask about aspects specifically. I like to think of aspects as packages. A package in a generic system (Fate, GURPS, Hero, Savage World) a bundle of traits (attributes, advantages, flaws, gifts, skills, etc) that describe an element of the setting. A campaign revolving around Navy Seals would have different packages for the different MOSs.
Now aspects in fate are natural language descriptions of some element in the setting. A Navy SEAL demolition specialist would have a demolition specialist aspect with benefits and limitations. A Super Porsche Amazing Engine would have an aspect of requiring Unobtainum as a fuel source with own attendant set of complications. The fact that a characters is from New York's Hell Kitchen can be an aspect with benefits and complications.
Remember per the Fate Core rules on page 56 an aspect is
Unique or noteworthy is why you don't need to list every attribute or bit of information about a thing or character as an aspect. Only the things that are important to the campaign should be made aspects.
It becomes part of the character when it's more important than the other aspects that they have. Something as ephemeral as the Create Advantage action probably won't change a character in such a fundamental way, and (probably) neither will getting an item.
Hmm. Example time:
We've got a character with a couple of aspects: "Always stand up against bullies" "Fight smarter, not harder" "I'd be super if I wasn't a little guy."
Some stuff happens, and you wind up in the army, and you get a cool prize if you get the flag from the top of the pole. No way your Mediocre (at best!) Athletics is going to Overcome the Great difficulty to get you up there, but you're smart so you use Notice to Create An Advantage to put the Aspect of "The pole is held up by a single pin". This allows you narrative permission to use Mechanics (or Notice, or something else) to Overcome, or maybe the difficulty goes down (or you just spend the free invoke or whatever). This aspect doesn't stick around, because it's no longer important to the story.
Later on, you get stuck in a machine, and collect a piece of equipment called "Super Soldier Serum". In addition to moving some of your skills around (and getting some stunts, and generally going from being a 92 pound skinny guy with bad lungs to a Super Soldier) you drop that "I'd be Super if I wasn't a little guy" for "Dr Erskine's Greatest Invention".
Also, in the Cap vein, things like his .45, or the various guns he picks up? They're stuff that gives him narrative permission to use combat (or just fluff in the description of the combat roll) The shield, on the other hand, could be described with an Aspect ("Shielded Super Soldier")
No, not all facts are aspects. Aspects are narratively relevant facts.
Making something an aspect is pointing it out, and saying that it's important. It's like a camera taking a shot to linger on the patch of ice on a rooftop - as soon as you see that, you know someone's slipping on it.
There's a sort of information economy in Fate, and things that are called out as aspects are things that are important. Making "everything an aspect" blows this information economy out of the water, and makes it useless.
Now, any fact can be an aspect, but only if it's important. Is it something that will be compelled or invoked?
If your game is a TV show, then the things you'd say that the TV show is "about" should be aspects. But not every fact needs to be.
Here's an article from one of the authors about "spamming" aspects: http://ryanmacklin.com/2013/11/fate-misconceptions-and-aspect-spamming/
Now, a lot of the "long-running facts' like you describe are certainly candidates for being aspects! Something like Hunted By Samaritan is a great aspect, because it allows for a Compel of "and this goes wrong when assassins show up" at any point.
All aspects are facts but not all facts are aspects. One way to differentiate an aspect from a mundane fact could be that aspects are prominent facts for the context they are attached to. They say a lot about what you want to emphasize in your game.
There may be other facts that rise from the narrative, and once established, those should be respected. However, unless they are somehow made into aspects, those facts do not affect the game mechanics at all.
That is because the game mechanics in Fate do not model the actual probabilities of various "facts" affecting the outcomes of some actions. Fate does not care if your gun is more accurate or if your car is faster.
The reason that aspects provide game-mechanical results is; aspects are facts that are important for the story, and you as a player get a bonus for weaving them into the narrative in an interesting way. Fate does care if you want to make your prototype sportscar or rusty vintage revolver an important part of the story.