Deadpool, The Fantastic Four and X-Men are all films by 20th Century Fox but does that exclude them from the Marvel Cinematic Universe? Deadpool is said to be littered with easter eggs, and easter eggs to me are links to other films, connecting them and showing that they are in the same universe and world. Also Quicksilver in X-Men: Days of Future Past is not the same Quicksilver in [The Avengers: Age Of Ultron](tag:293035), which shows that they can't be connected. However the Quicksilver in X-Men is a young Quicksilver and the Quicksilver in Avengers is an older version so they could connect up.
However on Marvel's official website on the movies section (http://marvel.com/movies/all) there is a section called 'Marvel Cinematic Universe' and X-Men, Deadpool and Fantastic 4 are not there. This clearly shows that they're not in the same universe by Marvel.
If these films aren't in the MCU do you think Marvel should make their own movie to place them in, or just weave the existing ones in?