Nathan Fillion plays actor Simon Williams (seen in movie posters). In the comics, Simon Williams was Wonder Man, an Avenger who had a very successful side career as a Hollywood action star who did his own stunts
Kurt Russell has appeared in many Disney films over the past fifty years. Guardians of the Galaxy Vol. 2 (2017) will be his first Disney film, and first superhero film, in twelve years, since Sky High (2005).
On March 23rd, 2016, Chris Pratt announced a fundraiser to help support the Lake Stevens Boys and Girls Club from where he grew up. By donating, you would get a chance to visit Pratt and eat lunch with him on the set of GOTG2.
In the second trailer, The Sweet's "Fox on the Run" plays in the background. In one of Suicide Squad's trailers, The Sweet's song "Ballroom Blitz" plays in its background. This is a coincidence because both songs appeared on the same album and Suicide Squad is also DC's answer to Marvel's Guardians, furthering the connections and coincidences.
In Guardians of the Galaxy (2014) a cocoon is seen in the Collector's collection. This cocoon is rumored to contain Adam Warlock who is a member of The Guardians in the comic. He is also rumored to appear in the sequel.
It has been confirmed that Groot (who was obliterated in the last film, only to be reborn as a little twiglet) will have a major role again, having reached adolescence. It has also been confirmed by the studio that he will have an extended vocabulary.
It is rumoured that Adam Warlock will appear in Guardians of the Galaxy Vol. 2 (2017), as his cocoon was seen in The Collector's collection during the end-credit scene of Thor: The Dark World (2013). Though it is not yet known what became of him when the collection exploded in Guardians of the Galaxy (2014). It has also been rumoured that the Soul Infinity Gem/Stone will appear with him.
Thanos will possibly appear in this movie to obtain the Aether and the Orb. He'll possibly be on Knowhere where the Collector's museum is to obtain the Aether aka the Reality Stone to put on his Infinity Gauntlet. Then journeys to Xandar to obtain the Orb for the Power Stone to put on his Infinity Gauntlet. Then plans his journey to Asgard for the Tesseract aka the Space Stone in the two following films later that year in Thor: Ragnarok (2017).
James Gunn described making Ego as Star-Lord's father a continuation of exploring the personal side of the Guardians: "If a raccoon could talk, and shoot a machine gun, how could that be? Answering that question ended up being the entire foundation of the first film. There's a sadness in these characters: Rocket was an animal experimented upon and torn apart; Groot has far more in common with Frankenstein's monster than with Bugs Bunny. Ego is an even more ridiculous character. But if a planet was alive, how could that be? And how could it father a child? Nova Prime said about Peter's father in the first film is that he is something ancient and unknown. And being a cosmic being, alone for eons, is even more lonely than being the universe's sole talking raccoon."
When James Gunn was writing the script for the movie and proposed the idea of Ego the Living Planet being Star-Lord's father, Marvel had told him that they didn't have the rights to Ego, whose rights were with 20th Century Fox because of his ties to the Fantastic Four and Silver Surfer franchises. Since Gunn did not have any other characters in mind for Star-Lord's father, he had to ask Fox if he could use the character. Fortunately, Fox agreed to let Marvel have Ego, in return for Fox have more creative freedom regarding Negasonic Teenage Warhead's set of superpowers in Deadpool (2016).