Regarding Wil Smith (from IMDb);
So yeah...I think he's out.
Will Smith was supposed to reprise the role of Captain Steven Hiller, but Fox refused to meet his request for a $50 million salary for two sequels. Roland Emmerich confirmed Smith was not be returning for the sequel in June 2013 to Daily News, but mentioned that Jeff Goldblum would return to reprise his role as David Levinson. Additionally, Maika Monroe replaced Mae Whitman as Patricia Whitmore. Whitman did not officially comment on the change, aside from a re-tweet of a HitFix article on her Twitter account titled "The case of the missing Mae Whitman and 'Independence Day 2'", implying she was never approached.
So yeah...I think he's out.