What exactly is Venom (2018)'s relationship with Marvel, Disney, and the MCU?

Question

As many know, the rights to certain Marvel film properties are not owned by Disney, but by Sony Pictures. In particular, this includes the characters of Spider-Man and Venom. Now, we all know that Spider-Man is currently part of the MCU under special agreement between Sony and Disney.

Yet it is claimed that Venom is not. In particular,

There's no mention any other part of the MCU in Venom (2018). And I've seen the argument on Youtube that the lines between Brock and Skirth in Venom stating that for there to be aliens is "completely crazy" means it can't possibly be the MCU since alien interference on Earth is very much public knowledge in the MCU (The Battles of New York and Wakanda, Thor, etc.)

On the other hand:

The title cards on Venom state that it is "in association with Marvel" and there is a cameo by Stan Lee, which is very much in keeping with MCU films.

So,

What exactly is the relationship between Venom (2018), Marvel, Disney, and the MCU?

Answer 1

It is not part of the MCU

In a live Facebook interview with French website, AlloCiné (that we managed to transcribe) Feige revealed that we won’t be seeing Holland and Hardy go toe-to-toe in the Marvel Cinematic Universe.

When asked about a potential appearance Feige explained:

“For now, there is NO plan for Venom in the MCU. It’s a Sony Project.”

_{Screen Geek, Kevin Feige Says There Are No Plans For VENOM In The Marvel Cinematic Universe}

And if this transcribed school Q/A is to be believed the Russo brothers have said the same thing on a different occasion.

Student: I have two- is the new venom movie going to be in the MCU?

Russo: No that’s a Sony property

In fact Sony has stated that Venom was meant to be the start of a new series of films set in "Sony's Marvel Universe".

Following Spider-Man: Homecoming, which will be released in the coming weeks, Sony has plans to release a spinoff film focusing on one of Spider-Man’s most recognizable villains, Venom. There are also plans for Silver Sable and Black Cat spinoffs, all tied into the Spider-Man world that Sony owns the rights to.

When Sony confirmed yesterday that Hardy would be playing Venom, the studio used an interesting phrase to define the universe that the film would belong to: Sony’s Marvel Universe.

_{Polygon, Sony’s Marvel Universe won’t actually connect to the Marvel Universe}

@SonyPictures: Tom Hardy is Eddie Brock in #Venom, the upcoming film from Sony’s Marvel Universe releasing October 5, 2018 – production starts this fall.

_{Twitter, @SonyPictures}

And to be clear Stan Lee being in a film has nothing to do with the Marvel Cinematic Universe just Marvel in general. For example, see the X-men Cinematic Universe with Deadpool and Deadpool 2 for some recent examples.